Environmental Engineering Reference
In-Depth Information
principal investigators the assurance that the software is correct [
117
]. This
was addressed to some extent in a previous book in this series [
119
].
In addition to being space-based, many of the proposed missions will op-
erate very remotely and without frequent contact with a ground-based opera-
tions control center or with a large communications lag time. Such conditions
make detecting and correcting software errors before launch even more impor-
tant, because patching the software during the mission's operational phase will
be di
cult, impractical, or impossible.
Autonomous missions are still at a relatively early stage of evolution in
NASA, and the software development community is still learning approaches
to their development. These are highly parallel systems that can have very
complex interactions. Even simple interacting systems can be dicult to de-
velop, as well as debug, test, and validate. In addition to being autonomous
and highly parallel, these missions may also have intelligence built into them,
and they can be distributed and can engage in asynchronous communications.
Consequently, these systems are dicult to verify and validate.
New verification and validation techniques are required [
100
,
113
,
118
,
120
,
124
]. Current techniques, based on large monolithic systems, have worked well
and reliably, but do not translate to these new autonomous systems, which
are highly parallel and nondeterministic.
11.3 Future Missions
Some future missions were discussed in other parts of this topic. The following
material from indicated sources describes additional mission concepts that are
undeniably ambitious in nature - the success of which will require autonomous
Table 11.1.
Some NASA future missions
Mission Launch date Number of spacecraft
BigBangObserver 2020+ Approx. 12
Black Hole Imager 2025+ Approx. 33
Constellation X 2020+ 1
Stellar Imager After 2020 Approx. 17
LISA 2020 3
MIDEX SIRA 2015+ 12-16
Enceladus 2018 2
Titan 2018 2
JWST 2013+ 1
LISA
Laser Interferometer Space Antenna;
MIDEX
Medium Explorer;
SIRA
Solar
Imaging Radio Array;
JWST
James Webb Space Telescope
1
The following descriptions are summarized from the NASA future missions web
site.
