Tech Briefs Magazine - September 2022 - 46

APPLICATION
BRIEFS
Raising the Reliability of Scientific
Space Exploration
LASP
Boulder, CO
https://lasp.colorado.edu/home/
AdaCore
New York, NY
www.adacore.com
T
he Laboratory for Atmospheric and Space Physics (LASP) at
the University of Colorado Boulder was founded in 1948, a
decade before NASA. It began as the Upper Air Laboratory,
using captured German V2 rockets to
send scientific instruments into our
planet's upper atmosphere.
Today, LASP continues to focus on
scientific research, both in the earth's
upper atmosphere and beyond. LASP
partners with government agencies
like NASA and the National Oceanic
and Atmospheric Administration,
commercial entities like Ball Aerospace,
and other universities like the
University of Arizona and Northern
Arizona University, to develop, test,
and operate spacecraft and scientific
instruments.
Projects in which LASP has participated
include NASA's Kepler space
telescope mission, the Mars Atmosphere
and Volatile Evolution Mission
(MAVEN), the Solar Radiation
and Climate Experiment (SORCE),
the Total and Spectral Solar Irradiance Sensor (TSIS-1), the
Emirates Mars Mission (EMM), and many others.
A Highly Scalable Command and Control
System
One of LASP's key tools for fulfilling its mission is the Operations
and Science Instrument Support-Command & Control
(OASIS-CC) software suite. OASIS-CC is LASP's in-house-developed,
ground-based, real-time command and control system
for spacecraft and instruments. It can be scaled from low-level
development through integration, test, and flight ops. LASP
has been using OASIS-CC in all its mission roles for more than
30 years.
The OASIS-CC project began in 1985 and chose Ada as the
implementation language. According to Jason Gurgel, the
OASIS-CC Program Manager at LASP, OASIS-CC uses a client
server model. The core server makes network connections to
scientific instruments, spacecraft systems, ground control systems,
other ground stations, ground instrumentation, simulators,
and other systems. The OASIS-CC client graphical
46
user interfaces (GUIs) allow users to design workspaces to
display command control panels, telemetry data, and additional
information.
OASIS-CC can be used to develop and test scientific instruments
in the laboratory and control those same instruments
during missions aboard spacecraft. By using OASIS-CC
throughout the life of a program, project managers can greatly
reduce both risk and cost by leveraging re-use.
Mission-Critical Software Must Remain Reliable
The heart of the OASIS-CC system - the client server portion
- is written in Ada. It has been certified as NASA Class B
software (Non-Human Space Rated Software Systems or LargeScale
Aeronautics Vehicles). One of LASP's big challenges, according
to Gurgel, is making sure that the mission-critical software
remains reliable.
LASP is constantly modifying OASIS-CC
to control new instruments.
And they need to be sure those expensive
instruments will work perfectly
throughout their mission when
doing so. Neither LASP nor their
partners can afford to have undefined
code behavior or other bugs
waste the money spent developing
and testing an instrument and sending
it into space.
" Naturally, any changes or new features
have to be thought about and
then thoroughly tested, " Gurgel said.
" That's just the nature of the software;
it's mission-critical. "
One of the big challenges of maintaining
the reliability of a 30-year-old
real-time system is keeping it up-todate,
manageable, and efficient.
That's why, in 2010, LASP decided to undertake a major overhaul
of OASIS-CC.
Until then, OASIS-CC had been a monolithic system - a single
program written in Ada 83. To make the system more efficient
and maintainable, LASP decided to repartition it and
update its code to a more modern version of Ada.
For the latter, LASP needed a new compiler. They had been
using a Verdix/Vads Ada 83 compiler from the 1980s. What
they wanted was a modern Ada compiler supported by a vendor
with deep Ada expertise. They were looking for a partner who
would aid them in their Ada upgrade and help them make sure
their software remained certified to NASA Class B.
A Total System Migration
LASP decided to refactor their entire code base and migrate
it from a SPARC/Solaris system to a Linux platform. They removed
all the GUI portions from the Ada code and reworked
the rest as a distributed client server, upgrading the code from
Ada 83 to Ada 95. Then, they wrote brand new C++ code for the
front end and the displays on all the GUIs.
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Tech Briefs Magazine - September 2022

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