Space access - Revision history

RichardWSmith: /* Cost to orbit */ x100 more realistic than x1,000

2024-10-26T23:39:15Z

Cost to orbit: x100 more realistic than x1,000

← Older revision		Revision as of 00:39, 27 October 2024
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	Note that the space shuttle was supposed to greatly lower the cost to reach space, but it failed. It was not really 'reusable' but rather 'refurbisable' taking months to inspect, repair, refurbish before it could launch again. Worse this took a team of hundreds of people. It ended up being one of the most expensive launchers.		Note that the space shuttle was supposed to greatly lower the cost to reach space, but it failed. It was not really 'reusable' but rather 'refurbisable' taking months to inspect, repair, refurbish before it could launch again. Worse this took a team of hundreds of people. It ended up being one of the most expensive launchers.

	Cost to LEO is arguably the most important contributor to space access for people. If the cost to reach space is hundreds of thousands of dollars, very few people will go. If the cost drops a ~~thousand~~ fold, then more opportunities open up, both recreational and economic.		Cost to LEO is arguably the most important contributor to space access for people. If the cost to reach space is hundreds of thousands of dollars, very few people will go. If the cost drops a hundred fold, then more opportunities open up, both recreational and economic.

	==Conventional rocket crafts==		==Conventional rocket crafts==

RichardWSmith: /* Cost to orbit */ Improved sentence.

2024-10-26T21:16:02Z

Cost to orbit: Improved sentence.

← Older revision		Revision as of 22:16, 26 October 2024
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	Note that the space shuttle was supposed to greatly lower the cost to reach space, but it failed. It was not really 'reusable' but rather 'refurbisable' taking months to inspect, repair, refurbish before it could launch again. Worse this took a team of hundreds of people. It ended up being one of the most expensive launchers.		Note that the space shuttle was supposed to greatly lower the cost to reach space, but it failed. It was not really 'reusable' but rather 'refurbisable' taking months to inspect, repair, refurbish before it could launch again. Worse this took a team of hundreds of people. It ended up being one of the most expensive launchers.

	~~This~~ is arguably the most important contributor to space access for people. If the cost to reach space is hundreds of thousands of dollars, very few people will go. If the cost drops a thousand fold, then more opportunities open up, both recreational and economic.		Cost to LEO is arguably the most important contributor to space access for people. If the cost to reach space is hundreds of thousands of dollars, very few people will go. If the cost drops a thousand fold, then more opportunities open up, both recreational and economic.

	==Conventional rocket crafts==		==Conventional rocket crafts==

RichardWSmith: /* Cost to orbit */ Talked about space shuttle, and importance of cost to orbit.

2024-10-26T21:15:08Z

Cost to orbit: Talked about space shuttle, and importance of cost to orbit.

← Older revision		Revision as of 22:15, 26 October 2024
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	The cost of space flight is a key concept. This is often measured as the cost to lift a kilogram into Low Earth Orbit (LEO). This cost has declined slowly for the last few decades, tho SpaceX has made this significantly lower by creating reusable rockets with a short turn around time.		The cost of space flight is a key concept. This is often measured as the cost to lift a kilogram into Low Earth Orbit (LEO). This cost has declined slowly for the last few decades, tho SpaceX has made this significantly lower by creating reusable rockets with a short turn around time.

	[[File: Cost_To_LEO.png~~\|thumb~~\|top\|px\| The cost of space flight has decreased in last 60 years]]		[[File: Cost_To_LEO.png\|top\|px\| The cost of space flight has decreased in last 60 years]]

			Note that the space shuttle was supposed to greatly lower the cost to reach space, but it failed. It was not really 'reusable' but rather 'refurbisable' taking months to inspect, repair, refurbish before it could launch again. Worse this took a team of hundreds of people. It ended up being one of the most expensive launchers.

			This is arguably the most important contributor to space access for people. If the cost to reach space is hundreds of thousands of dollars, very few people will go. If the cost drops a thousand fold, then more opportunities open up, both recreational and economic.

	==Conventional rocket crafts==		==Conventional rocket crafts==

RichardWSmith: /* Cost to orbit */ Trying to add picture.

2024-10-26T21:09:18Z

Cost to orbit: Trying to add picture.

← Older revision		Revision as of 22:09, 26 October 2024
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	==Cost to orbit==		==Cost to orbit==
	The cost of space flight is a key concept. This is often measured as the cost to lift a kilogram into Low Earth Orbit (LEO). This cost has declined slowly for the last few decades, tho SpaceX has made this significantly lower by creating reusable rockets with a short turn around time.		The cost of space flight is a key concept. This is often measured as the cost to lift a kilogram into Low Earth Orbit (LEO). This cost has declined slowly for the last few decades, tho SpaceX has made this significantly lower by creating reusable rockets with a short turn around time.

			[[File: Cost_To_LEO.png\|thumb\|top\|px\| The cost of space flight has decreased in last 60 years]]

	==Conventional rocket crafts==		==Conventional rocket crafts==

RichardWSmith: /* DeltaV and energy */ Added section on Cost to Orbit.

2024-10-26T21:02:23Z

DeltaV and energy: Added section on Cost to Orbit.

← Older revision		Revision as of 22:02, 26 October 2024
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	==DeltaV and energy==		==DeltaV and energy==
	The [[w:Delta-v_budget\|deltaV]] to orbit for Mars is about 3,8 km/s. For Earth, taking into account atmospheric friction the deltaV is about 9.3 to 10 km/s. Using the rocket equation Δv=ve*ln(Mo/Mf) or ''Mo/Mf''= e(Δv/ve) we can see that the mass fraction of propellant to reach orbit is much lower for Mars than for Earth. For example with Methane and Oxygen propellant, the exhaust velocity (ve) is about 3400m/s, so for Mars the mass ratio is 3, while for Earth it is between 15 and 19. So it is at least five times easier to leave Mars than it is to leave Earth.		The [[w:Delta-v_budget\|deltaV]] to orbit for Mars is about 3,8 km/s. For Earth, taking into account atmospheric friction the deltaV is about 9.3 to 10 km/s. Using the rocket equation Δv=ve*ln(Mo/Mf) or ''Mo/Mf''= e(Δv/ve) we can see that the mass fraction of propellant to reach orbit is much lower for Mars than for Earth. For example with Methane and Oxygen propellant, the exhaust velocity (ve) is about 3400m/s, so for Mars the mass ratio is 3, while for Earth it is between 15 and 19. So it is at least five times easier to leave Mars than it is to leave Earth.

			==Cost to orbit==
			The cost of space flight is a key concept. This is often measured as the cost to lift a kilogram into Low Earth Orbit (LEO). This cost has declined slowly for the last few decades, tho SpaceX has made this significantly lower by creating reusable rockets with a short turn around time.

	==Conventional rocket crafts==		==Conventional rocket crafts==

Michel Lamontagne: /* Speculative concepts */

2023-10-03T13:39:25Z

Speculative concepts

← Older revision		Revision as of 14:39, 3 October 2023
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	*A [[mass driver]] is powered electrical and requires no chemical propellants. While on Earth this would not work for lifting people to orbit, the conditions of Mars might allow it. However a mass driver capable of sending payloads into orbit is a large infrastructure.		*A [[mass driver]] is powered electrical and requires no chemical propellants. While on Earth this would not work for lifting people to orbit, the conditions of Mars might allow it. However a mass driver capable of sending payloads into orbit is a large infrastructure.
	*A [[Sky ramps\|Sky ramp]] on Mars would allow inexpensive and high thru-put single stage to orbit vehicles.		*A [[Sky ramps\|Sky ramp]] on Mars would allow inexpensive and high thru-put single stage to orbit vehicles.
	*Chemical propellants on Mars will be produced by solar arrays or nuclear reactors, through the electrolysis of water. So chemical propulsion on Mars is actually electrical in nature.		*Chemical propellants on Mars will be produced by solar arrays or nuclear reactors, through the electrolysis of water. So chemical propulsion on Mars is actually electrical in nature and ultimately solar or nuclear powered.

	==references==		==references==

Michel Lamontagne: /* Motivation */

2023-10-03T13:38:25Z

Motivation

← Older revision		Revision as of 14:38, 3 October 2023
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	==Motivation==		==Motivation==
	A human [[colony]] on Mars can be established with or without space access. The fight against the gravitational pull requires large amounts of [[energy]]. Since the [[gravity]] of [[Mars]] is smaller than [[Earth]]' and the [[atmosphere]] is thinner, space access is easier. However, the energy resources of such a colony are limited. Using parts of the available energy for space access could be thought to reduce other project's progress.		A human [[colony]] on Mars can be established with or without space access. The fight against the gravitational pull requires large amounts of [[energy]]. Since the [[gravity]] of [[Mars]] is smaller than [[Earth]]' and the [[atmosphere]] is thinner, space access is easier. However, the energy resources of such a colony are limited. Using parts of the available energy for space access could be thought to reduce other project's progress. However, space access is required for return to earth, and is likely to be part of any human occupied flights to Mars.

	However, space access for a martian settlements also means that there is a way to return the transportation vehicle back to Earth and re-use it. This will greatly reduce the cost of transportation from Earth to Mars. This is the [[In-situ resource utilization\|In-situ]] ~~ressources~~ paradigm.		However, space access for a martian settlements also means that there is a way to return the transportation vehicle back to Earth and re-use it. This will greatly reduce the cost of transportation from Earth to Mars. This is the [[In-situ resource utilization\|In-situ]] resources paradigm.

	Beyond returning the transportation vehicles back to Earth for re-use, Assuming the colonists went to Mars to stay there and build their own civilization, there still might be some additional tasks to do:		Beyond returning the transportation vehicles back to Earth for re-use, Assuming the colonists went to Mars to stay there and build their own civilization, there still might be some additional tasks to do:

	*Trips to Low Mars Orbit and possible space stations residing there for scientific reasons		*Trips to Low Mars Orbit and possible space stations residing there for scientific reasons.
	*Trips to [[Phobos]] and [[Deimos]] for scientific and mining reasons.		*Trips to [[Phobos]] and [[Deimos]] for scientific and mining reasons.
	*Ferry persons to and from space craft that have arrived from, or are heading for, Earth, or other celestial bodies. For example, the Mars cycler concept.		*Ferry persons to and from space craft that have arrived from, or are heading for, Earth, or other celestial bodies. For example, the Mars cycler concept.
	*Possible satellite repair, not a dissimilar task as to what was imagined for the [[space shuttle]] in the 1970's		*Possible satellite repair, not a dissimilar task as to what was imagined for the [[space shuttle]] in the 1970's.

	==DeltaV and energy==		==DeltaV and energy==

Michel Lamontagne: /* Conventional rocket crafts */

2023-10-03T13:35:18Z

Conventional rocket crafts

← Older revision		Revision as of 14:35, 3 October 2023
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	It has proved very difficult to build an SSTO launcher on Earth, but the lower Martian [[gravity]] would be of assistance to any launching spacecraft. If the craft uses multiple stages, these will all have to be recovered separately, which complicates the process of reuse. [[SpaceX]] has proposed a combination vehicle that is SSTO on Mars, but TSTO on Earth. The combination of [[Starship]] and Falcon super heavy, or [[Booster]].		It has proved very difficult to build an SSTO launcher on Earth, but the lower Martian [[gravity]] would be of assistance to any launching spacecraft. If the craft uses multiple stages, these will all have to be recovered separately, which complicates the process of reuse. [[SpaceX]] has proposed a combination vehicle that is SSTO on Mars, but TSTO on Earth. The combination of [[Starship]] and Falcon super heavy, or [[Booster]].

	Hydrogen, methane and oxygen propellants can be obtained from ~~martian~~ ice. The attitude control thrusters could use gaseous oxygen and methane, kept under pressure.		Hydrogen, methane and oxygen propellants can be obtained from Martian ice. The attitude control thrusters could use gaseous oxygen and methane, kept under pressure.

	Early landers will probably be non-reusable or only partially reusable. The descent stages of these landers could be dismantled and reused.		Early landers will probably be non-reusable or only partially reusable. The descent stages of these landers could be dismantled and reused.

	The guidance systems on the lander need not be [[hi-tech versus lo-tech\|hi-tech]]. The Apollo spacecraft flew to the Moon using less computing power then a pocket calculator. ~~A simple computer~~, or a ~~[[pneumatics\|pneumatic]] system could be used. Although there~~ are advantages ~~with hi-tech systems, lo-tech systems could be included as a backup~~.		The guidance systems on the lander need not be [[hi-tech versus lo-tech\|hi-tech]]. The Apollo spacecraft flew to the Moon using less computing power then a pocket calculator. However, due to the many variables in a landing sequence and the availability of technology low tech solutions are very unlikely and don't offer any significant advantages.

	However, precise landing to a dedicated landing pad ~~would~~ require advanced adaptive control techniques, as otherwise the probable landing area is ~~often~~ measured in tens of km<sup>2</sup>.		However, precise landing to a dedicated landing pad will require advanced adaptive control techniques, as otherwise the probable landing area is measured in tens to hundreds of km<sup>2</sup>

	==Speculative concepts==		==Speculative concepts==

RichardWSmith: /* Speculative concepts */

2022-10-08T11:49:07Z

Speculative concepts

← Older revision		Revision as of 12:49, 8 October 2022
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	*A [[space elevator]] is an interesting alternative both for Luna and Mars. Probably, it allows even more cost reduction. However, Phobos' orbit may intersect the path of a martian space elevator.		*A [[space elevator]] is an interesting alternative both for Luna and Mars. Probably, it allows even more cost reduction. However, Phobos' orbit may intersect the path of a martian space elevator.
	*A [[mass driver]] is powered electrical and requires no chemical propellants. While on Earth this would not work for lifting people to orbit, the conditions of Mars might allow it. However a mass driver capable of sending payloads into orbit is a large infrastructure.		*A [[mass driver]] is powered electrical and requires no chemical propellants. While on Earth this would not work for lifting people to orbit, the conditions of Mars might allow it. However a mass driver capable of sending payloads into orbit is a large infrastructure.
	*A [[Sky ramp]] on Mars would allow inexpensive and high thru-put single stage to orbit vehicles.		*A [[Sky ramps\|Sky ramp]] on Mars would allow inexpensive and high thru-put single stage to orbit vehicles.
	*Chemical propellants on Mars will be produced by solar arrays or nuclear reactors, through the electrolysis of water. So chemical propulsion on Mars is actually electrical in nature.		*Chemical propellants on Mars will be produced by solar arrays or nuclear reactors, through the electrolysis of water. So chemical propulsion on Mars is actually electrical in nature.

RichardWSmith: Added link.

2022-10-08T11:48:12Z

Added link.

← Older revision		Revision as of 12:48, 8 October 2022
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	*A [[space elevator]] is an interesting alternative both for Luna and Mars. Probably, it allows even more cost reduction. However, Phobos' orbit may intersect the path of a martian space elevator.		*A [[space elevator]] is an interesting alternative both for Luna and Mars. Probably, it allows even more cost reduction. However, Phobos' orbit may intersect the path of a martian space elevator.
	*A [[mass driver]] is powered electrical and requires no chemical propellants. While on Earth this would not work for lifting people to orbit, the conditions of Mars might allow it. However a mass driver capable of sending payloads into orbit is a large infrastructure.		*A [[mass driver]] is powered electrical and requires no chemical propellants. While on Earth this would not work for lifting people to orbit, the conditions of Mars might allow it. However a mass driver capable of sending payloads into orbit is a large infrastructure.
			*A [[Sky ramp]] on Mars would allow inexpensive and high thru-put single stage to orbit vehicles.
	*Chemical propellants on Mars will be produced by solar arrays or nuclear reactors, through the electrolysis of water. So chemical propulsion on Mars is actually electrical in nature.		*Chemical propellants on Mars will be produced by solar arrays or nuclear reactors, through the electrolysis of water. So chemical propulsion on Mars is actually electrical in nature.