APPENDIX A
Space Physics Missions (1958-2000)
INTRODUCTION
This appendix examines the processes involved in obtaining observations from space, which were discussed briefly in Chapter 6. This examination was motivated by a concern over the long time delays between the start of a mission and the return of scientific data which became common in the late 1980s and early 1990s. We start by considering the time from the start of a mission to launch of the spacecraft. We take the starting date as the date that investigators submitted proposals to place instruments on the spacecraft. We chose the proposal date because it is a well-defined starting point that exists in some form for most missions. However, we recognize that it is not the "actual" starting time for the ideas that led to the mission. For instance, NASA administrators first have to be convinced to start, or at least investigate, a mission prior to issuing an Announcement of Opportunity for investigators. In several cases we discuss this preannouncement development stage as well. (A date of July 1 is used when only the year is known. When a proposal date is not available, we use an estimated date on which the "concept" development started for the mission.)
INTERVAL FROM PROPOSAL TO LAUNCH FOR MAGNETOSPHERIC MISSIONS
Missions Started in the 1960s
In this section we consider missions for which one or more investigators submitted proposals in the 1960s. Table A.1 shows a representative list of
TABLE A.1 Space-Physics-Related Launches in the 1960s
Mission |
Start |
Launch |
Time to Launch |
Lead Agency |
Pioneer 2 |
5/1958 |
11/1958 |
6 mo |
NASA |
Explorer 6 |
7/1958 |
8/1959 |
1 yr 1 mo |
NASA |
Pioneer 5 |
1/1959* |
3/1960 |
1 yr 2 mo |
NASA |
Discoverer 31 |
7/1960* |
8/1961 |
1 yr 1 mo |
NASA |
Discoverer 33 |
7/1960* |
9/1961 |
1 yr 2 mo |
NASA |
Discoverer 36 |
7/1960* |
12/1961 |
1 yr 5 mo |
NASA |
IMP 1 |
12/1960* |
11/1963 |
2 yr 11 mo |
NASA |
OGO 1 |
7/1962* |
9/1964 |
2 yr 2 mo |
NASA |
IMP 2 |
1/1961* |
10/1964 |
3 yr 9 mo |
NASA |
Mariner 4 |
7/1962 |
11/1964 |
2 yr 4 mo |
NASA |
IMP 3 |
12/1960* |
5/1965 |
4 yr 6 mo |
NASA |
OGO 2 |
7/1962* |
10/1965 |
3 yr 3 mo |
NASA |
Pioneer 6 |
7/1963* |
12/1965 |
2 yr 5 mo |
NASA |
OGO 3 |
7/1962* |
6/1966 |
3 yr 11 mo |
NASA |
Pioneer 7 |
7/1963* |
8/1966 |
3 yr 1 mo |
NASA |
ATS 1 |
2/1965 |
12/1966 |
1 yr 10 mo |
NASA |
OGO 4 |
7/1962* |
7/1967 |
5 yr |
NASA |
IMP 4 |
12/1964* |
5/1967 |
2 yr 6 mo |
NASA |
OGO 5 |
8/1964 |
3/1968 |
3 yr 7 mo |
NASA |
OGO 6 |
3/1966 |
6/1969 |
3 yr 3 mo |
NASA |
IMP 5 |
7/1965* |
6/1969 |
3 yr 11 mo |
NASA |
IMP 6 |
7/1968 |
7/1971 |
3 yr |
NASA |
Pioneer 10 |
7/1969 |
3/1972 |
2 yr 8 mo |
NASA |
IMP 7 |
11/1966 |
9/1972 |
5 yr 10 mo |
NASA |
Pioneer 11 |
7/1969 |
4/1973 |
3 yr 9 mo |
NASA |
IMP 8 |
11/1966 |
10/1973 |
6 yr 11 mo |
NASA |
AEC |
7/1969 |
12/1973 |
4 yr 5 mo |
NASA |
Mariner 10 |
7/1969* |
11/1973 |
4 yr 4 mo |
NASA |
ATS 6 |
7/1968 |
5/1974 |
5 yr 10 mo |
NASA |
Viking |
7/1969 |
7/1975 |
6 yr |
NASA |
* Mission concept date used. |
missions from this period. An asterisk indicates missions for which the concept date is used. The time from proposal to launch for our sample varied from less than two years to nearly seven years. Several of the missions took three to four years. One of the shortest was ATS 1, which took one year and ten months. ATS 1 was designed to test communications technology and was not originally intended to carry any scientific instruments. However, in early 1965 the decision was made to include a small number of scientific instruments. These had to be completed quickly to keep the project on schedule. The spacecraft with the longest development interval was IMP 8. IMP was a scientific spacecraft, and its development was originally planned to take six years, with launch in 1972. It
should be noted that IMP 8 was still providing valuable solar wind data 18 years after launch.
Missions Started in the 1970s
Table A.2 lists several missions started in the 1970s. The Voyager and the International Sun Earth Explorer (ISEE) missions took about five years from proposal to launch. Both were scientifically successful missions. ISEE reentered the Earth's atmosphere in 1987 after 10 years in orbit, while the Voyagers are still returning heliospheric data after having probed the magnetospheres of Jupiter, Saturn, Uranus, and Neptune.
The Dynamics Explorer (DE) mission provides a good example of the effort required to define and sell a mission concept in the 1970s. The DE mission was designed to study the atmosphere, ionosphere, and magnetosphere as a system. Conferences laying the foundation for the DE mission began as early as 1972. During the fall of 1973 the scientific concepts on which the DE mission was based were presented to the Office of Space Science at NASA Headquarters. In April 1974 a planning and feasibility study group was established at the Goddard Space Flight Center (GSFC), and in July 1974 an Announcement of Opportunity (AO) was released that solicited proposals for Explorer-type payloads. Many of the proposals submitted in response to this AO were for the Electrodynamics Explorer (EE) program.
An EE study team was appointed in 1975. It issued a report describing the mission, and in May 1976 NASA made the final selection of investigators for the mission. A project plan was prepared by GSFC, and a cost review was conducted at NASA Headquarters. Following this review it was decided that the EE project could not be implemented as outlined. However, the scientific communi
TABLE A.2 Space Physics Related Missions in the 1970s
Mission |
Start |
Launch |
Time to Launch |
Lead Agencies |
ISEE 3 |
9/1972 |
8/1978 |
5 yr 11 mo |
NASA |
Pioneer Venus |
10/1973 |
5/1978 |
4 yr 7 mo |
NASA |
DE 1 and 2 |
7/1974 |
8/1981 |
7 yr 1 mo |
NASA |
AMPTE U.K., Germany |
7/1972 |
8/1984 |
12 yr 1 mo |
NASA, |
Spacelab |
9/1976 |
8/1985 |
9 yr 1 mo |
NASA |
Galileo |
11/1976 |
10/1989 |
12 yr 11 mo |
NASA |
Ulysses |
8/1977 |
10/1990 |
13 yr 2 mo |
ESA, NASA |
UARS |
12/1978 |
9/1991 |
12 yr 9 mo |
NASA |
ty had made a very strong case that the scientific problems EE was to attack were of the highest priority in space physics. So in January 1977 a smaller mission, Dynamics Explorer, was started. The investigators for this smaller mission were chosen in May 1977. Funding authorization for the program was received in October 1977, and the two DE spacecraft were launched Jess than four years later.
The final mission during the 1970s was Galileo. The Galileo proposals were written in 1976. The original launch was scheduled for 1982, but problems with the spacecraft and with the Space Shuttle launch system caused it to be postponed until 1986. The launch was further delayed until 1989 by the Challenger explosion. However, even if the Challenger explosion had not occurred, the interval between proposals and launch still would have been nine years.
Missions Started in the 1980s
During the 1980s the time between the selection of experiments for a mission and the actual launch became very large (Table A.3). The Combined Release and Radiation Effects Satellite (CRRES) mission was started in 1981. Originally, it was an Air Force project called RADSAT. In 1982 it was combined with the NASA Chemical Release Program. After a number of delays, including the Challenger accident, CRRES was launched in 1990.
The International Solar-Terrestrial Physics (ISTP) program resulted from a series of studies conducted by committees of the National Research Council's Space Sciences Board (SSB) in the late 1970s and early 1980s. Among these was the Kennel report1, which cited six critical regions of the terrestrial magnetosphere that needed to be better understood in order to understand the time-dependent exchange of energy and plasma between the solar wind and the magnetosphere. From this the Origins of Plasma in the Earth's Neighborhood (OPEN) program evolved. In the OPEN program spacecraft would be flown simultaneously in four key regions: the WIND spacecraft would monitor the solar wind, the POLAR spacecraft would observe in the polar region, EQUATOR would provide observations in the near-earth magnetotail equatorial region, and GEOTAIL would probe both the near-earth and distant magnetotail. Proposals for participation in the OPEN mission were written in 1980. During the design phase of the mission it became evident that the costs would exceed the available resources. Since understanding the global flow of energy throughout a system as vast as the magnetosphere required the four spacecraft at a minimum, it was decided to seek international cooperation. This led to the formation of ISTP. Under ISTP the Japanese Institute of Space and Astronautical Science
TABLE A.3 Space-Physics-Related Missions in the 1980s
Mission |
Start |
Launch (actual or expected) |
Time to Launch |
Lead Agencies |
CRRES |
7/1981 |
7/1990 |
9 yr |
DoD, NASA |
SAMPEX |
9/1988 |
7/1992 |
3 yr 9 mo |
NASA |
ISTP/Geotail |
3/1980 |
7/1992 |
12 yr 4 mo |
ISAS, NASA |
ISTP/Wind |
3/1980 |
9/1994 |
14 yr 6 mo |
NASA |
ISTP/Polar |
3/1980 |
6/1995 |
15 yr 3 mo |
NASA |
FAST |
7/1988 |
7/1994 |
6 yr |
NASA |
ISTP/Cluster |
7/1988 |
12/1995 |
7 yr 5 mo |
ESA |
CRAF |
11/1985 |
7/1996 |
10 yr 8 mo |
NASA |
ACE |
7/1986 |
8/1997 |
11 yr 1 mo |
NASA |
Cassini |
2/1990 |
7/1997 |
7 yr 5 mo |
NASA, ESA |
SOHO |
7/1989 |
7/1995 |
6 yr |
ESA, NASA |
(ISAS) took the lead in the GEOTAIL spacecraft. The European Space Agency agreed to provide four spacecraft that would fly in a tetrahedral formation to probe the polar magnetosphere, magnetopause, and cusp (CLUSTER). The EQUATOR spacecraft was canceled. It was hoped that data from the CRRES spacecraft would partially fill the gap left by the cancellation of EQUATOR, but CRRES stopped operating in 1991. The ISTP mission was approved in 1988. The GEOTAIL spacecraft was launched in July 1991, 12 years after the initial proposal. Unfortunately, the schedules for the WIND and POLAR spacecraft have slipped recently, and it will be at least mid- to late 1995 before they are launched.
The Fast Auroral Snapshot Explorer (FAST) is a small explorer mission. It will provide high-resolution observations in the auroral zone. In this small explorer program the entire instrument complement was proposed as a unit with a single principal investigator. The proposals were written in 1988, and the current schedule calls for a 1994 launch.
The time difference between the proposal and launch date for each mission, which provides a measure of the implementation time, has been plotted versus launch date in Figure A.1. Explorer and other NASA missions are shown in the Figure, with future missions indicated by arrows that represent the effect of a one-year delay. The implementation time has steadily increased over the past three decades, with the result that most recent missions have taken approximately 12 years to be implemented.