Human Spaceflight: A Worthy Replacement For The ISS?!

[Torquemadus]

NASA is currently the only space agency to have sent humans beyond Low Earth Orbit. Since Apollo, NASA has been tied up with the expensive Space Shuttle program. More recently, it has been focused on building and operating the ISS, which has also consumed a great deal of time and money. We could endlessly debate the relative costs versus the benefits of these programs. However, they have nonetheless kept NASA tied up in LEO.

Thankfully, an end to this deadlock is in sight. The Shuttle has stopped flying, and the Space Station will also stop flying at some point in the 2020s. Concurrent with this, we see a rear guard action being fought by the "old space" establishment, with the use of Space Shuttle era technology to build the SLS heavy lift rocket, which is suitable for launching missions to interplanetary destinations. There are concerns about the cost effectiveness of SLS, but it does nonetheless demonstrate a strong political commitment in principle to human spaceflight beyond Low Earth Orbit. At the same time, we see "new space" finally starting to come of age. Commercial space companies are sending cargo to the ISS at prices that "old space" could have only dreamed of achieving. Commercial crew will follow soon. Proposals to adapt such systems to un-crewed BEO missions are already being submitted. http://www.nasaspaceflight.com/2015/05/falcon-heavy-dragon-solar-system-explorer/

The big change is that there is an acknowledgement that the ISS will have to be followed by something beyond Low Earth Orbit. However, NASA are currently constrained to develop missions based around SLS and Orion, along with the "old space" thinking that goes with them. We therefore hear of expensive "flags and footprints" mission proposals that cost too much and achieve too little. We had already heard of the Constellation program, which offered to replicate the Apollo missions of almost fifty years ago (at much greater cost). More recently, we hear of proposed Mars missions that either don't land at all, or offer ineffectual "short stay" (flags and footprints only) missions that achieve very little actual exploration. We are assured that these missions will nonetheless allow astronauts to perform exploration through telerobotics, which offer the advantage of reduced time delay compared to operation from Earth, but don't even come close to justifying the increase cost and risk to the astronauts' lives in undertaking such missions!

It's little wonder then that many have drawn comparisons to the huge returns achieved by NASA's JPL robotic missions. Studies undertaken at Moon and Mars analogues on Earth have shown that human investigators can offer vast advantages over robotic missions, but only if they have sufficient time and mobility to exploit their advantages! It has been estimated that the useful data return from the three day "J Class" Apollo missions (Apollo 15, 16 and 17) is roughly equivalent to a Mars rover mission such as Opportunity or Curiosity conducted over several years. If human explorers can only visit destinations such as the Moon and Mars for a few days, or at most a few weeks, then there is no way that the increased cost and danger can be justified!

The biggest obstacle to present day useful human spaceflight is the cost of space transportation and logistical support and their destination location. The obvious way to address this problem is to buy transportation services from "new space". Let's look at the ISS as an example: The ISS is considered to be the pinnacle of present day human spaceflight achievement. Most of the transportation services required to support the ISS are provided by or purchased from the Russians. This is because the Russians are offering lower prices. "New Space" companies are now being allowed to compete for the chance to send cargo and crew to the ISS. Sooner or later, the ISS will stop flying. Current NASA proposals for Mars missions make no use of Commercial Space or International Partners. What will the international space community do once the ISS stops flying?

An obvious solution is to allow a combination of international cooperation and "New Space" to provide transportation services to BEO bases supported by In-Situ Resource Utilisation. The best solution that has been offered so far is Robert Zubrin's Mars Direct plan. This concept may not be familiar to everyone. I'll summarise it here as best I can. This plan was originally designed to be used in the "Old Space" environment, using Shuttle derived launch vehicles. The plan is however readily adaptable to "New Space".

Zubrin's plan solves the logistic problems of Mars missions by producing the fuels and consumables needed for Mars exploration from local materials instead of importing them from Earth. The chemical reactors needed to do this have already been tested in simulated Mars environments. Martian resources are used not only to sustain the crew on the surface, but are also used to provide liquid fuels to run ground vehicles and auxiliary power generators.

The crew spend six months flying to Mars, using tethered artificial gravity to protect their bodies from de-conditioning. Radiation protection is provided by a solar flare storm shelter. Cosmic ray dosage (total Mars spaceflight mission dosages have already experienced by long duration Earth orbiting astronauts) has already been assessed. The crew stay on Mars for a year and a half, making use of their mobility to explore large areas of the Martian surface. Once resources on the surface have been properly assessed, a site will be chosen for a permanent base.

Since the launch window to Mars only opens every two years: there will be ample opportunity to support a Moon base and missions to LEOs.

[Nibb31]

Please see the other threads that cover Zubrin's plan. It's not realistic at all in the current environment.

[xenomorph555]

Also to add in, "new space" won't be going to BEO after ISS's decommission for a long time. Instead they will stay in LEO ferrying to newer stations and other tourism based activities, if that ever takes off of course. Of course not all will survive, some resupply business' will be lost inevitably and those company's will have to revert to satellites.

As for title of the thread, here are some realistic proposals for replacements;

Skylab-2

OPSEK

Russian Lunar Orbital Station

Tiangong-3

Bigelow Alpha

BRIC's Station

A combination

[Kibble]

Tiangong-3

Considering that NASA is prohibited to work with China - could American commercial spaceflight companies negotiate directly with CNSA for participation? The Commercial Crew vehicles still wouldn't bee a way for American astronauts to visit, but could we see resupply missions or Commercial Crew ferrying ESA astronauts and international tourists?

Edited May 17, 2015 by Kibble

[Nibb31]

Why would China give up their prestige by hiring commercial services from US companies? The whole point of any space program is to subsidize domestic R&D.

[Kryten]

ESA were looking into potential co-operation the Chinese station program, but AFAIK that only extended to ESA astronauts on Shenzhou and perhaps supply flights.

[xenomorph555]

Considering that NASA is prohibited to work with China - could American commercial spaceflight companies negotiate directly with CNSA for participation? The Commercial Crew vehicles still wouldn't bee a way for American astronauts to visit, but could we see resupply missions or Commercial Crew ferrying ESA astronauts and international tourists?

Why would China give up their prestige by hiring commercial services from US companies? The whole point of any space program is to subsidize domestic R&D.

ESA were looking into potential co-operation the Chinese station program, but AFAIK that only extended to ESA astronauts on Shenzhou and perhaps supply flights.

I put SL-2, OPSEK and T-3 on the list because while they may not be international (although it is possible for O or T-3 to gain foreign modules/astronauts), they are space stations and therefore count as "replacements" for ISS.

[fredinno]

I believe a permanent research Space station is essential to Space development, but we can, and will, do better than we did with the ISS, cost wise. Inflatable modules and dry/wet workshops are the future, allowing us to reduce construction launches and costs significantly.

[Torquemadus]

To be specific: I'm looking at human spaceflight programs that will provide a worthy space exploration goal once the ISS stops flying.

There will most certainly be other space stations flown in LEO. Some have been proposed by national space agencies as a technological stepping stone prior to attempting missions to BEO destinations. If the International Space Station had been truly international in scope, there would be no need for a separate Chinese or BRICs' station. These represent an unnecessary duplication of effort!

Commercially operated stations have also been proposed. Hotels, research labs, and specialised manufacturing facilities have all been suggested. These ventures would be entirely paid for by private capital as for-profit business ventures. These are dependant on lowering of launch costs to levels deemed acceptable to potential investors and customers.

As far as NASA is concerned, there is a requirement for a space exploration program that takes the agency beyond Low Earth Orbit. US taxpayers are currently funding the development of SLS and Orion. These have been promised as a means of flying exploration missions to Mars in the 2030s. However, these missions offer "flags and footprints" with little meaningful exploration achieved. These missions are designed to keep SLS and Orion occupied, but make no mention of what Commercial Space and any international partners are supposed to do with themselves while all of this is happening.

Assuming a very conservative outlook from all concerned, NASA could abandon their Mars ambitions and concentrate on establishing an internationally operated Moon base. Many of the national space agencies have announced their own Moon plans concurrent with the George Bush Junior Vision for Space Exploration (VSE). The main obstacle to Mars missions is the lack of suitable launch vehicles and transportation systems needed to get there. Once a Moon base was established, it wouldn't be terribly difficult to take the next step and establish a similar base on Mars, or other BEO destinations.

The main initial incentive for establishing a Moon base would be the construction of interferometer telescopes. While space-based telescopes can observe frequencies that are not observable from Earth, and the far side of the Moon offers a radio emissions quiet dead zone for radio astronomy, the Moon offers the added advantage of a geologically dead platform for building long-exposure interferometers. These are telescope arrays that require extremely precise knowledge of the distances between the telescopes in the array. Geological activity prevents the construction of such arrays on Earth. Orbital mechanics prevents construction of free floating arrays in space. In principle, the aperture size of such arrays is limited only by the size of the Moon itself.

Think of the scientific discoveries offered by the Hubble Space Telescope and the Kepler planet hunter mission. Imagine what discoveries could be made by Moon based telescopes with the advantage of long exposure times and effectively unlimited aperture sizes and image resolution?! Such telescopes could allow us to unlock the secrets of the early Universe, allowing us to study the formation of early galaxies and stars. They will also allow us to directly image exoplanets, allowing us to learn as much about them as we can presently learn about our interplanetary neighbours using present day telescopes. Just as Hubble offered the secrets of our universe to the Stephen Hawkings of our day, so will giant telescope arrays offer unimagined knowledge to the physicists of future generations.

Earth's moon is resource poor and is ill-suited to large scale human settlement, but that doesn't mean that it has no value to a spacefaring human civilisation.

A more ambitious plan would be to send humans to Mars. Mars is a long-term goal that offers the prospect of a new branch of human civilisation. Mars is seen by some as too far away and too hard, but it can be reached with the same chemical propulsion systems needed to reach Earth's Moon.

Mars is the most Earth-like destination available in our own solar system. It can support food production and industrialised civilisation. Additionally, it lies within easy reach of the main asteroid belt.

Robert Zubrin's Mars Direct plan allows for simultaneous establishment of Moon and Mars bases as well as outposts on Near Earth Asteroids. What matters is that outposts can be established in places that can be readily supported by space transportation services offered by both "Old Space" and "New Space". Just as the ISS is currently supported by commercial cargo and crew, so can BEO outposts be supported in the same way. International partners can support transportation to any or all of these destinations.

Edited May 17, 2015 by Torquemadus

[Nibb31]

As far as NASA is concerned, there is a requirement for a space exploration program that takes the agency beyond Low Earth Orbit. US taxpayers are currently funding the development of SLS and Orion. These have been promised as a means of flying exploration missions to Mars in the 2030s. However, these missions offer "flags and footprints" with little meaningful exploration achieved.

You've got NASA's requirements wrong.

If the goal is exploration, then manned spaceflight is not a requirement. Exploration does not need boots on the ground. It can be done with robots much more efficiently.

The only goal of manned spaceflight is manned spaceflight. It is "studying how to live in space so that humans can live in space", which is a circular justification that doesn't make much sense. The purpose is prestige and subsidizing technology development.

Robert Zubrin's Mars Direct plan allows for simultaneous establishment of Moon and Mars bases as well as outposts on Near Earth Asteroids. What matters is that outposts can be established in places that can be readily supported by space transportation services offered by both "Old Space" and "New Space". Just as the ISS is currently supported by commercial cargo and crew, so can BEO outposts be supported in the same way. International partners can support transportation to any or all of these destinations.

Zubrin's plan is a pipe dream. It is still way beyond NASA's budget, and doesn't take into account the latest knowledge of Mars' chemical and radiation environment or the current TRLs of technology that is required to safely get people to Mars and back.

Edited May 18, 2015 by Nibb31

[Reddragon]

The only goal of manned spaceflight is manned spaceflight. It is "studying how to live in space so that humans can live in space"

Which doesn't require going beyond LEO I think.

[Nibb31]

Which doesn't require going beyond LEO I think.

Well, you could expand it to "the only point of sending humans to [extreme environment of your choice] is to study how to send humans to [extreme environment of your choice]". That extreme environment could be the Antarctic, the bottom of the ocean or the surface of Europa. My point was that it's a pointless endeavour unless sending humans to [extreme environment of your choice] carries some other added value, which in the case of Mars, it doesn't really.

[fredinno]

You've got NASA's requirements wrong.

If the goal is exploration, then manned spaceflight is not a requirement. Exploration does not need boots on the ground. It can be done with robots much more efficiently.

The only goal of manned spaceflight is manned spaceflight. It is "studying how to live in space so that humans can live in space", which is a circular justification that doesn't make much sense. The purpose is prestige and subsidizing technology development.

Robots are relatively inexpensive, but are ineffective in the way that they have a much harder time getting a lot done in a short time. Human spaceflight may be expensive, but, generally speaking, can get more science done in a much shorter time, for shorter stays. Humans can also build colonies and expand human presence; robots cannot.

The only goal of manned spaceflight is not manned spaceflight. It can be, but manned spaceflight also extends down to other reaches of science- Material science, biology, chemistry, etc.

Besides, ISS primarily took so long and so much money due to the launch vehicles at the time. A ISS replacement could almost certainly be launched with less than 25% of ISS cost using dry workshops. It would also only take 4 SLS Block II Launches to launch the entire weight of the ISS to LEO.

[Nibb31]

Robots are relatively inexpensive, but are ineffective in the way that they have a much harder time getting a lot done in a short time. Human spaceflight may be expensive, but, generally speaking, can get more science done in a much shorter time, for shorter stays. Humans can also build colonies and expand human presence; robots cannot.

Time is irrelevant. There is no urgency so no need to get a lot done in a short time. The laws of physics are not changing and the rocks on Mars will be there for a while. We can take our time to design a robot that can do any task that a human can do for a fraction of the cost.

And it will take at least 20 years for humans to reach Mars. In 20 years, it's pretty safe to imagine that robotics and AI will be more advanced than today.

As for colonies, there is no economic incentive to build any, no reason for people to mess migrate off world, and no political will. It's not going to happen any time soon.

The only goal of manned spaceflight is not manned spaceflight. It can be, but manned spaceflight also extends down to other reaches of science- Material science, biology, chemistry, etc.

Only human biology, which proves my point. Material science and chemistry can be studied by robotic experiments. Plant biology and even small animals can be studied remotely too.

[fredinno]

"As for colonies, there is no economic incentive to build any, no reason for people to mess migrate off world, and no political will. It's not going to happen any time soon."

And yet the expansion of the human civilisation is essential to our long-term future.

[Kibble]

"As for colonies, there is no economic incentive to build any, no reason for people to mess migrate off world, and no political will. It's not going to happen any time soon."

And yet the expansion of the human civilisation is essential to our long-term future.

The key phrase there was "any time soon".

[Nibb31]

"As for colonies, there is no economic incentive to build any, no reason for people to mess migrate off world, and no political will. It's not going to happen any time soon."

And yet the expansion of the human civilisation is essential to our long-term future.

Why would that be? What sort of event would leave less survivors on Earth than in a hypothetical space colony? Even a scorched Earth will always be more hospitable than Mars or the Moon. If we can build self-sufficient colonies on Mars, then surely we can build self-sufficient colonies on an uninhabitable Earth with far less effort.

Edited May 19, 2015 by Nibb31