View Full Version : Spaceflight without ground control
2011-Nov-13, 12:32 PM
The following though occured to me one day.
Cars operate autonomously. Ships operate autonomously. Aircraft operate autonomously. They have air traffic control so they don't crash into each other, but that's it.
Spacecrafts are a different bunch. Even when they are crewed, they relay a complete telemetry back to Earth, and rely on an army of people down here to analyze it, find the problems and work out the solution. The crew is up there only to follow instructions not think for themselves. Even during Apollo, the primary navigation system was a ground-based radar.
On the other hand in the old sci-fi books, spacecrafts are treated as they were ships -- i.e. it's the crew supposed to be navigating solving problems, not the ground control.
One problem with keeping your support crew back on Earth is that it severely limits how many missions can be supported at the same time. So even if we could cheaply fly a lot of spacecrafts, we would become limited by the cost of control centers.
An interplanetary civilization would require a lot of spacecrafts flying around the Solar System every day -- too many to be practically controlled from the ground. These would necessarily have to be largely autonomous.
What do you think?
2011-Nov-13, 01:26 PM
I don't really see that. Pretty sure that having as many people on the ground as possible will be cheaper than launching them into space.
2011-Nov-13, 01:27 PM
Quite a few of our more recent probes are becoming autonomous for longer periods of time:
- The Mars MER Rover(s) get their instructions in the form of targets, and then execute it, sometimes traveling 100 meters without further control, avoiding hazards, etc.
- The Dawn spacecraft is using relative autonomy for navigation as well.
Things on this front are most likely very primitive compared to technology for autonomy that will be available when you call us an interplanetary civilization.
2011-Nov-13, 02:03 PM
I really don't know the details, but to my casual observations there certainly seems to be a downward trend in the amount of ground control per probe or meat sack. Just one of the advantages of improved information technology I presume, and I would expect this trend to continue.
2011-Nov-13, 08:14 PM
Spacecrafts...crewed...relay a complete telemetry back to Earth, and rely on an army of people down here to analyze it, find the problems and work out the solution...in the old sci-fi books, spacecrafts are treated as they were ships -- i.e. it's the crew supposed to be navigating solving problems, not the ground control...One problem with keeping your support crew back on Earth is that it severely limits how many missions can be supported at the same time. So even if we could cheaply fly a lot of spacecrafts, we would become limited by the cost of control centers...
The current mission control model is due to several factors:
(1) On-board processing from Mercury through Shuttle was limited. Mercury had no on-board digital computer, those with Gemini and Apollo were very crude, even Shuttle was limited by today's standards. They didn't have sufficient hardware and software capability for extensive on-board monitoring and real-time analysis of thousands of data channels. The solution was radio the data back to earth for analysis.
(2) All manned spacecraft including shuttle are R&D vehicles not production vehicles. Each mission is a test flight. When airplanes are test flown today, thousands of telemetry channels are sent to earth. Manned spacecraft don't have purpose-built "black box" flight recorders. From Mercury through shuttle, it would have been impossible or very difficult to have a totally armored, independently-powered, highly ruggedized recorder storing thousands of channels, some at 100 times per second. Again the solution was telemetry. If something really bad happens the data is saved on earth. That said Columbia had a development data recorder called MADS, intended for use on test flights to record certain parameters which exceeded telemetry capability. Fortunately it was left active and by a miracle survived the Columbia disaster, even though it wasn't designed to.
With today's technology, ruggedized, survivable data recording of many thousand channels is possible, eliminating one reason for telemetry on manned spacecraft.
Early sci-fi depictions of space travel were depicted as limited in voice communications, and telemetry was rarely even mentioned. This was due to several factors:
(1) Authors were unaware of then-current electronic and telemetry capability.
(2) It was more dramatically compelling to depict space travelers as isolated "polar expedition"-type explorers.
(3) Film production of a smaller cast and simpler set was cheaper than a huge mission control set. In those days audience and readers were not often unaware of "mission control"-style operations, so the cheaper route (from a film production standpoint) was considered adequate.
(4) The ability to reliably telemeter large amounts of data over long distances (esp. to deep space) was only developed during the early 1960s. General awareness of this sea change naturally lagged the reality. It took extensive signal processing, world-spanning data communications networks, and huge radio telescope dishes repurposed as communications antennas. Early during Apollo development, knowledgeable planners assumed the primary nav method would be via on-board via inertial nav and computers. It was *after* Apollo was in active development that earth-based radar navigation was improved to be the main mode, vs on-board nav. So it's not just early Sci-Fi writers being uninformed. The most technically informed people -- those working on Apollo development, weren't sure earth-based navigation and control would be possible.
With today's technology, things have come full circle. It's now possible to have mostly on-board navigation, data recording and analysis -- If that is deemed the best way by future decision makers. Certainly for a manned Mars mission that must be the approach, as light travel time would not permit rapid assessment of telemetered data on earth.
We see harbingers of this in aviation. Originally commercial aircraft had a flight crew of 5 -- pilot, co-pilot, navigator, radio man, and flight engineer. One by one all positions except pilot and co-pilot were replaced by increasingly sophisticated electronics and computers. Instead of a flight engineer scrutinizing a wall of analog gauges, computers monitor the data, evaluate it, and notify the pilot or co-pilot only if necessary. Likewise communications and navigation are so automated that the reduced workload can be handled by the smaller flight crew. In similar ways a future spacecraft would have advanced computers which filter and analyze the data for the crew, not necessarily requiring scores of mission control engineers.
Mission-control-style operations do not limit the scalability of future manned space missions. The capability already exists to do missions with much greater on-board autonomy and reduced ground-based mission personnel.
2011-Nov-14, 09:42 AM
Hells, we are seen signs of it already. How many people are at Mission Control when the Falcon 1 takes off? There is other support personnel and a manned mission, being significantly more complicated will have more people. But, as time goes on, I do see this potentially changing. It will have to as we explore farther and farther from Earth.
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