MARS-500
The MARS-500 project is a Russian simulation of a round trip space flight from Earth to Mars and back. It is being conducted near Moscow.
One of the previous experiments apparently included violence and a sexual assault! Hopefully this won't someday happen on a real mission...
What's a little strange to me is that the experiment is mainly about the behavior of a group of humans confined in a small, isolated and sometimes dangerous environment. This is hardly new to human experience, though it might be to a group of young and highly educated technical professionals representative of a space flight crew. Until the last century it was common for groups of men to sail around the world for years in cramped ships, with no modern conveniences, carrying all their food and supplies (except for what they could fish from the sea), occasionally facing extreme dangers, completely cut off from the outside world.
Certainly no manned trip to Mars would have to do without computers or communications, and I think they'd play the central role in keeping a Mars crew occupied and sane.
The Apollo astronauts carried a few favorite songs to the moon on cassette tapes that they recorded over with dictation as needed. But computer storage technology has already reached the point where there's no technological reason a Mars-bound ship can't carry a major fraction of all the books, movies and music albums that will exist on earth on the day of launch. The astronauts certainly wouldn't be bored for lack of anything to read, watch or listen to.
Except for a few days out of each year around solar conjunction, there will also be continuous communications with earth, and there's no reason to limit it to Mission Control. The astronauts could easily be given direct Internet access, though some sort of access control is needed to protect the uplink from malicious congestion.
But as the ship leaves earth, the speed-of-light delay will increase linearly with distance and the available data rate will decrease with the square of the distance. The distance from Earth to Mars ranges widely, from about 1/2 AU at opposition to 2.5 AU at solar conjunction, so even when the mission is at Mars the round trip delay will range from 4 minutes to over 20 and the achievable throughput (for the same antennas, frequencies and power levels) will vary by a factor of 25:1.
Obviously nothing can be done to increase the speed of light. You have to adapt to it. No matter how high the link throughput, you can't get even one bit of information before one light round trip time. You can request information in anticipation of needing it, but link capacity is limited and you don't want to spend it on transferring information that you never use.
We have various experimental protocols designed to maintain high throughput over links with high bandwidth*delay products. Throughput is objective and easily measured, but it's just one criteria out of many. It also assumes that the file is larger than the bandwidth*delay product, and that's especially unreasonable when the delay is in minutes.
All this could make for an interesting experiment for a project like MARS-500.
What applications and network protocols should be provided to a group of Mars-bound human astronauts? How would they actually use them? Mission related traffic would obviously have priority over personal traffic, but how would the astronauts allocate link capacity among themselves when there's not enough for everything? Is email, or an email-like file transfer service, the only workable application with round trip delays measured in minutes? And how would the crew use them?
In his classic essay "The Cathedral and the Bazaar", Eric Raymond explained that "Every good work of software starts by scratching a developer's personal itch". This strongly suggests that the best way to develop the communication protocols and usage strategies for a Mars mission is to add an experienced network programmer to the crew of a simulated mission and let him devise and use his own communication protocols. I really think this would work, and if I were a lot younger I'd even consider volunteering myself.
One of the previous experiments apparently included violence and a sexual assault! Hopefully this won't someday happen on a real mission...
What's a little strange to me is that the experiment is mainly about the behavior of a group of humans confined in a small, isolated and sometimes dangerous environment. This is hardly new to human experience, though it might be to a group of young and highly educated technical professionals representative of a space flight crew. Until the last century it was common for groups of men to sail around the world for years in cramped ships, with no modern conveniences, carrying all their food and supplies (except for what they could fish from the sea), occasionally facing extreme dangers, completely cut off from the outside world.
Certainly no manned trip to Mars would have to do without computers or communications, and I think they'd play the central role in keeping a Mars crew occupied and sane.
The Apollo astronauts carried a few favorite songs to the moon on cassette tapes that they recorded over with dictation as needed. But computer storage technology has already reached the point where there's no technological reason a Mars-bound ship can't carry a major fraction of all the books, movies and music albums that will exist on earth on the day of launch. The astronauts certainly wouldn't be bored for lack of anything to read, watch or listen to.
Except for a few days out of each year around solar conjunction, there will also be continuous communications with earth, and there's no reason to limit it to Mission Control. The astronauts could easily be given direct Internet access, though some sort of access control is needed to protect the uplink from malicious congestion.
But as the ship leaves earth, the speed-of-light delay will increase linearly with distance and the available data rate will decrease with the square of the distance. The distance from Earth to Mars ranges widely, from about 1/2 AU at opposition to 2.5 AU at solar conjunction, so even when the mission is at Mars the round trip delay will range from 4 minutes to over 20 and the achievable throughput (for the same antennas, frequencies and power levels) will vary by a factor of 25:1.
Obviously nothing can be done to increase the speed of light. You have to adapt to it. No matter how high the link throughput, you can't get even one bit of information before one light round trip time. You can request information in anticipation of needing it, but link capacity is limited and you don't want to spend it on transferring information that you never use.
We have various experimental protocols designed to maintain high throughput over links with high bandwidth*delay products. Throughput is objective and easily measured, but it's just one criteria out of many. It also assumes that the file is larger than the bandwidth*delay product, and that's especially unreasonable when the delay is in minutes.
All this could make for an interesting experiment for a project like MARS-500.
What applications and network protocols should be provided to a group of Mars-bound human astronauts? How would they actually use them? Mission related traffic would obviously have priority over personal traffic, but how would the astronauts allocate link capacity among themselves when there's not enough for everything? Is email, or an email-like file transfer service, the only workable application with round trip delays measured in minutes? And how would the crew use them?
In his classic essay "The Cathedral and the Bazaar", Eric Raymond explained that "Every good work of software starts by scratching a developer's personal itch". This strongly suggests that the best way to develop the communication protocols and usage strategies for a Mars mission is to add an experienced network programmer to the crew of a simulated mission and let him devise and use his own communication protocols. I really think this would work, and if I were a lot younger I'd even consider volunteering myself.