Ka-band high-rate telemetry system upgrade for the NASA deep space network

The NASA Deep Space Network (DSN) has a new requirement to support high-data-rate Category A (Cat A) missions (within 2 million kilometers of the Earth) with simultaneous S-band uplink, S-band downlink and Ka-band downlink. The S-band links are required for traditional telemetry, tracking & command (TT&C) support to the spacecraft, while the Ka-band link is intended for high-data-rate science returns. The new Ka-band system combines the use of proven DSN cryogenic designs, for low system temperature, and high-data-rate capability using commercial telemetry receivers. The initial Cat A support is required for the James Webb Space Telescope (JWST) in 2014 and possibly other missions. The upgrade has been implemented into 3 different 34-meter Beam Waveguide (BWG) antennas in the DSN, one at each of the complexes in Canberra (Australia), Goldstone (California) and Madrid (Spain). System test data are presented to show that the requirements were met and the DSN is ready for Cat A Ka-band operational support.     

The Phoenix signal detection system

The Phoenix system is based on that developed for the Targeted Search element of the former NASA High Resolution Microwave Survey (HRMS). The Phoenix system was used at the Parkes 64 m and Mopra 22 m antennas of the Australian Telescope National Facility in the first part of 1995. The system consists of: (1) an RF/IF subsystem providing 1–3 GHz coverage; (2) a search subsystem with a 20 MHz, dual-polarization search bandwidth; (3) a two-site, pseudo-interferometric follow-up subsystem that reobserves interesting signals found by the search subsystem; and (4) a control subsystem capable of automatic searching.     

Improved cost monitoring and control through the Earned Value Management System

As economic pressure and competition for budget among federal agencies has increased, there has been an increasing need for more granular data and robust management information systems. This is especially true for the execution of major civilian space programs. This need has resulted in new program management requirements being implemented in an attempt to limit cost and schedule growth. In particular, NASA Procedural Requirements (NPR) 7120.5D requires the implementation of an Earned Value Management System (EVMS) compliant with the requirements of American National Standards Institute (ANSI)/Electronic Industries Alliance Standard 748-B. The Radiation Belt Storm Probes (RBSP) program management team at The Johns Hopkins University Applied Physics Laboratory (JHU/APL) made a decision to implement an EVMS on RBSP during Phase B—a year earlier than specified in the contractual Phase C reporting requirement as defined in the NPR. This decision was made so that the project would have the benefit of 12 months of training and hands-on implementation during Phase B. Although there were a number of technical and process hurdles encountered during Phase B and into Phase C, the system was working well when the Integrated Baseline Review (IBR) was held in August 2009. The IBR was a success because it met the review requirements. It was also clear to all IBR participants that the EVMS was providing value to the project management team. Although the IBR pointed out some areas of concern regarding process and ANSI compliance, the system had markedly improved the project's ability to monitor cost and schedule. This, in turn, allowed the project team to foresee problems in advance, formulate corrective actions, and implement course corrections without causing significant adverse impact to the project. Opponents of EVMS systems often communicate the unfavorable opinion that EVMS systems create unnecessary cost and administration. Although it is undeniable that EVMS implementation does not occur without cost, the cost is minimal in comparison to the benefits of successful implementation. This paper will focus on the implementation of EVMS on the RBSP project, explain EV processes and the implementation's cost, and analyze the benefits of EVMS to provide insight into cost/benefit considerations for other projects considering EVMS implementation. This paper will do this by focusing on the following points: (1) RBSP is the first full-up implementation of earned value management (EVM) at JHU/APL; (2) RBSP EVM started in Phase B; (3) RBSP EVM implementation has been working well in Phase C/D; (4) RBSP EVM implementation has been recognized by Goddard Space Flight Center and NASA Headquarters as successful; and (5) an assessment of the benefits of EVMS to the project management team and sponsor shows that the system's benefits outweigh the cost of implementation.     

国外中继卫星对航天器交会对接的测控通信支持

中继卫星系统的天基测控通信是近代航天技术的重大突破,它能够有效地满足航天器交会对接的测控通信需要。文章分析了美国＂跟踪与数据中继卫星系统＂（TDRSS）和欧洲＂阿特米斯＂（ARTEMIS）中继卫星对＂自动转移飞行器＂（ATV）与＂国际空间站＂（ISS）交会对接任务的测控通信支持,总结了国外中继卫星系统支持航天器交会对接...     

Tracking and data relay satellite system: NASA's new spacecraft data acquisition system

The growth in NASA's ground network complexity and cost triggered a search for an alternative. Through a lease service contract, Western Union will provide to NASA 10 years of space communications services with a Tracking and Data Relay Satellite System (TDRSS). A constellation of four operating satellites in geostationary orbit and a single ground terminal will provide complete tracking, telemetry and command service for all of NASA's Earth orbital satellites below an altitude of 12,000 km. The system is shared: two satellites will be dedicated to NASA service; a third will provide backup as a shared spare; the fourth satellite will be dedicated to Western Union's Advanced Westar commercial service. Western Union will operate the ground terminal and provide operational satellite control. NASA's Network Control Center will provide the focal point for scheduling user services and controlling the interface between TDRSS and the rest of the NASA communications network, project control centers and data processing facilities. TDRSS single access user spacecraft data systems should be designed for efficient time shared data relay support. Reimbursement policy and rate structure for non-NASA users are currently being developed.     

The Suess-Urey mission (return of solar matter to Earth)

The Suess-Urey (S-U) mission has been proposed as a NASA Discovery mission to return samples of matter from the Sun to the Earth for isotopic and chemical analyses in terrestrial laboratories to provide a major improvement in our knowledge of the average chemical and isotopic composition of the solar system. The S-U spacecraft and sample return capsule will be placed in a halo orbit around the L1 Sun-Earth libration point for two years to collect solar wind ions which implant into large passive collectors made of ultra-pure materials. Constant Spacecraft-Sun-Earth geometries enable simple spin stabilized attitude control, simple passive thermal control, and a fixed medium gain antenna. Low data requirements and the safety of a Sun-pointed spinner, result in extremely low mission operations costs.     

SSETO—Small Satellite for Exoplanetary Transit Observation

SSETO is the result of a phase-A study in context of the small satellite program of the University of Stuttgart that demonstrates the capability of a university institute to build a small satellite with a budget of 5 million Euro. The satellite will be capable of observing exoplanets in a Neptune–Earth scale and obtaining data of interstellar dust. Due to a system failure of NASA?s Kepler mission, there is currently (October 2013) a lack of satellites searching for exoplanets. This paper details the design of subsystems and payload, as well as the required test tasks in accordance with the mission profile at a conceptional level. The costs for standard spacecraft testing and integration tasks are included, but not those of launch, ground support, operations and engineer working hours.     

Autonomous aerobraking for low-cost interplanetary missions

Aerobraking has previously been used to reduce the propellant required to deliver an orbiter to its desired final orbit. In principle, aerobraking should be possible around any target planet or moon having sufficient atmosphere to permit atmospheric drag to provide a portion of the mission ΔV, in lieu of supplying all of the required ΔV propulsively. The spacecraft is flown through the upper atmosphere of the target using multiple passes, ensuring that the dynamic pressure and thermal loads remain within the spacecraft's design parameters. NASA has successfully conducted aerobraking operations four times, once at Venus and three times at Mars. While aerobraking reduces the fuel required, it does so at the expense of time (typically 3–6 months), continuous Deep Space Network (DSN) coverage, and a large ground staff. These factors can result in aerobraking being a very expensive operational phase of the mission. However, aerobraking has matured to the point that much of the daily operation could potentially be performed autonomously onboard the spacecraft, thereby reducing the required ground support and attendant aerobraking related costs. To facilitate a lower-risk transition from ground processing to an autonomous capability, the NASA Engineering and Safety Center (NESC) has assembled a team of experts in aerobraking and interplanetary guidance and control to develop a high-fidelity, flight-like simulation. This simulation will be used to demonstrate the overall feasibility while exploring the potential for staff and DSN coverage reductions that autonomous aerobraking might provide. This paper reviews the various elements of autonomous aerobraking and presents an overview of the various models and algorithms that must be transformed from the current ground processing methodology to a flight-like environment. Additionally the high-fidelity flight software test bed, being developed from models used in a recent interplanetary mission, will be summarized.     

Experimental results of the Japanese BSE program

The Japanese Medium-scale Broadcasting Satellite for Experimental Purpose (BSE) is a three axis stabilized spacecraft having a Sun-oriented solar array for high power generation. This paper will present the BSE mission objectives, spacecraft and ground systems configurations and some of experimental results on TV broadcasting, K-band radio-wave propagation, etc.     

归因于空间环境的航天器故障与异常

天然空间环境对航天器设计、研制和运行的影响是NASA马歇尔空间飞行中心系统分析和集成实验室电磁与航空宇宙环境部组织编写的一系列NASA RP报告的主题.其中,NASA RP-1390详细概述了天然空间环境7个主要环境因素,包括它们的简单定义、相关的型号计划事项以及对各种航天器分系统的影响.该报告提供100多个从1974...     

SciBox,an end-to-end automated science planning and commanding system

SciBox is a new technology for planning and commanding science operations for Earth-orbital and planetary space missions. It has been incrementally developed since 2001 and demonstrated on several spaceflight projects. The technology has matured to the point that it is now being used to plan and command all orbital science operations for the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission to Mercury. SciBox encompasses the derivation of observing sequences from science objectives, the scheduling of those sequences, the generation of spacecraft and instrument commands, and the validation of those commands prior to uploading to the spacecraft. Although the process is automated, science and observing requirements are incorporated at each step by a series of rules and parameters to optimize observing opportunities, which are tested and validated through simulation and review. Except for limited special operations and tests, there is no manual scheduling of observations or construction of command sequences. SciBox reduces the lead time for operations planning by shortening the time-consuming coordination process, reduces cost by automating the labor-intensive processes of human-in-the-loop adjudication of observing priorities, reduces operations risk by systematically checking constraints, and maximizes science return by fully evaluating the trade space of observing opportunities to meet MESSENGER science priorities within spacecraft recorder, downlink, scheduling, and orbital-geometry constraints.     

Piloted operations at a near-Earth object (NEO)

In late 2006, NASA's Constellation Program sponsored a study to examine the feasibility of sending a piloted Orion spacecraft to a near-Earth object. NEOs are asteroids or comets that have perihelion distances less than or equal to 1.3 astronomical units, and can have orbits that cross that of the Earth. Therefore, the most suitable targets for the Orion Crew Exploration Vehicle (CEV) are those NEOs in heliocentric orbits similar to Earth's (i.e. low inclination and low eccentricity). One of the significant advantages of this type of mission is that it strengthens and validates the foundational infrastructure of the United States Space Exploration Policy and is highly complementary to NASA's planned lunar sortie and outpost missions circa 2020. A human expedition to a NEO would not only underline the broad utility of the Orion CEV and Ares launch systems, but would also be the first human expedition to an interplanetary body beyond the Earth–Moon system. These deep space operations will present unique challenges not present in lunar missions for the onboard crew, spacecraft systems, and mission control team. Executing several piloted NEO missions will enable NASA to gain crucial deep space operational experience, which will be necessary prerequisites for the eventual human missions to Mars.Our NEO team will present and discuss the following:

• new mission trajectories and concepts;

• operational command and control considerations;

• expected science, operational, resource utilization, and impact mitigation returns; and

• continued exploration momentum and future Mars exploration benefits.

Transforming solar system exploration: The origins of the Discovery Program, 1989–1993

The Discovery Program is a rarity in the history of NASA solar system exploration: a reform program that has survived and continued to be influential. This article examines its emergence between 1989 and 1993, largely as the result of the intervention of two people: Stamatios “Tom” Krimigis of the Johns Hopkins University Applied Physics Laboratory (APL), and Wesley Huntress of NASA, who was Division Director of Solar System Exploration 1990–92 and the Associate Administrator for Space Science 1992–98. Krimigis drew on his leadership experience in the space physics community and his knowledge of its Explorer program to propose that it was possible to create new missions to the inner solar system for a fraction of the existing costs. He continued to push that idea for the next two years, but it took the influence of Huntress at NASA Headquarters to push it on to the agenda. Huntress explicitly decided to use APL to force change on the Jet Propulsion Laboratory and the planetary science community. He succeeded in moving the JPL Mars Pathfinder and APL Near Earth Asteroid Rendezvous (NEAR) mission proposals forward as the opening missions for Discovery. But it took Krimigis's political skill and access to Sen. Barbara Mikulski in 1993 to get the NEAR into the NASA budget, thereby likely ensuring that Discovery would not become another one-mission program.     

The Voyager Interstellar Mission

The Voyager Interstellar Mission began on January 1, 1990, with the primary objective being to characterize the interplanetary medium beyond Neptune and to search for the transition region between the interplanetary medium and the interstellar medium. At the start of this mission, the two Voyager spacecraft had already been in flight for over twelve years, having successfully returned a wealth of scientific information about the planetary systems of Jupiter, Saturn, Uranus, and Neptune, and the interplanetary medium between Earth and Neptune. The two spacecraft have the potential to continue returning science data until around the year 2020. With this extended operating lifetime, there is a high likelihood of one of the two spacecraft penetrating the termination shock and possibly the heliopause boundary, and entering interstellar space before that time. This paper describes the Voyager Interstellar Mission--the mission objectives, the spacecraft and science payload, the mission operations system used to support operations, and the mission operations strategy being used to maximize science data return even in the event of certain potential spacecraft subsystem failures. The implementation of automated analysis tools to offset and enable reduced flight team staffing levels is also discussed.     

Optimal reconfiguration maneuvers for spacecraft imaging arrays in multi-body regimes

Upcoming National Aeronautics and Space Administration (NASA) mission concepts include satellite arrays to facilitate imaging and identification of distant planets. These mission scenarios are diverse, including designs such as the terrestrial planet finder-occulter (TPF-O), where a monolithic telescope is aided by a single occulter spacecraft, and the micro-arcsecond X-ray imaging mission (MAXIM), where as many as 16 spacecraft move together to form a space interferometer. Each design, however, requires precise reconfiguration and star tracking in potentially complex dynamic regimes. This paper explores control methods for satellite imaging array reconfiguration in multi-body systems. Specifically, optimal nonlinear control and geometric control methods are derived and compared to the more traditional linear quadratic regulators, as well as input state feedback linearization. These control strategies are implemented and evaluated for the TPF-O mission concept.     

Optimal reconfiguration maneuvers for spacecraft imaging arrays in multi-body regimes

Upcoming National Aeronautics and Space Administration (NASA) mission concepts include satellite arrays to facilitate imaging and identification of distant planets. These mission scenarios are diverse, including designs such as the terrestrial planet finder-occulter (TPF-O), where a monolithic telescope is aided by a single occulter spacecraft, and the micro-arcsecond X-ray imaging mission (MAXIM), where as many as 16 spacecraft move together to form a space interferometer. Each design, however, requires precise reconfiguration and star tracking in potentially complex dynamic regimes. This paper explores control methods for satellite imaging array reconfiguration in multi-body systems. Specifically, optimal nonlinear control and geometric control methods are derived and compared to the more traditional linear quadratic regulators, as well as input state feedback linearization. These control strategies are implemented and evaluated for the TPF-O mission concept.     

美国小行星俘获任务及其启示

小行星俘获(ACR)任务是美国Keck空间研究中心发起的一项深空探测任务。该任务计划选定一颗近地小行星,通过口袋式抓捕系统对其实施抓捕,并于2025年左右将其带回近月空间。文章介绍了ACR任务的内容和系统设计,具体包括:航天器总体构型、抓捕分系统、探测识别分系统和控制与推进分系统;对小行星抓捕的目标探测与识别、旋转匹配、抓捕、消旋、轨道转移等核心操作。基于ACR任务,提出了空间目标俘获技术的需求与应用、抓捕航天器系统设计的启示;基于我国目前的技术研究情况,总结分析了发展空间目标俘获任务所需的关键技术,如大功率柔性太阳翼、长时间大范围轨道机动、目标探测与识别、快速机动、目标抓捕与消旋。     

Portable end-to-end ground system for low-cost mission support

This paper presents a revolutionary architecture of the end-to-end ground system to reduce overall mission support costs. The present ground system of the Jet Propulsion Laboratory (JPL) is costly to operate, maintain, deploy, reproduce, and document. In the present climate of shrinking NASA budgets, this proposed architecture takes on added importance as it should dramatically reduce all of the above costs. Currently, the ground support functions (i.e., receiver, tracking, ranging, telemetry, command, monitor and control) are distributed among several subsystems that are housed in individual rack-mounted chassis. These subsystems can be integrated into one portable laptop system using established Multi Chip Module (MCM) packaging technology and object-based software libraries. The large scale integration of subsystems into a small portable system connected to the World Wide Web (WWW) will greatly reduce operations, maintenance and reproduction costs. Several of the subsystems can be implemented using Commercial Off-The-Shelf (COTS) products further decreasing non-recurring engineering costs. The inherent portability of the system will open up new ways for using the ground system at the “point-of-use” site as opposed to maintaining several large centralized stations. This eliminates the propagation delay of the data to the Principal Investigator (PI), enabling the capture of data in real-time and performing multiple tasks concurrently from any location in the world. Sample applications are to use the portable ground system in remote areas or mobile vessels for real-time correlation of satellite data with earth-bound instruments; thus, allowing near real-time feedback and control of scientific instruments. This end-to-end portable ground system will undoubtedly create opportunities for better scientific observation and data acquisition.     

NanoSail-D: A solar sail demonstration mission

In the early to mid-2000s, NASA made substantial progress in the development of solar sail propulsion systems. Solar sail propulsion uses the solar radiation pressure exerted by the momentum transfer of reflected photons to generate a net force on a spacecraft. To date, solar sail propulsion systems were designed for large robotic spacecraft. Recently, however, NASA has been investigating the application of solar sails for small satellite propulsion. The NanoSail-D is a subscale solar sail system designed for possible small spacecraft applications. The NanoSail-D mission flew on board the ill-fated Falcon Rocket launched August 2, 2008, and due to the failure of that rocket, never achieved orbit. The NanoSail-D flight spare is ready for flight and a suitable launch arrangement is being actively pursued. This paper will present an introduction solar sail propulsion systems and an overview of the NanoSail-D spacecraft.     

NASA'S Robotic Lunar Lander Development Project

Over the last 5 years, NASA has invested in development and risk-reduction activities for a new generation of planetary landers capable of carrying instruments and technology demonstrations to the lunar surface and other airless bodies. The Robotic Lunar Lander Development Project (RLLDP) is jointly implemented by NASA Marshall Space Flight Center (MSFC) and the Johns Hopkins University Applied Physics Laboratory (APL). The RLLDP team has produced mission architecture designs for multiple airless body missions to meet both science and human precursor mission needs. The mission architecture concept studies encompass small, medium, and large landers, with payloads from a few tens of kilograms to over 1000 kg, to the Moon and other airless bodies. To mature these concepts, the project has made significant investments in technology risk reduction in focused subsystems. In addition, many lander technologies and algorithms have been tested and demonstrated in an integrated systems environment using free-flying test articles. These design and testing investments have significantly reduced development risk for airless body landers, thereby reducing overall risk and associated costs for future missions.