Ares I is part of a proposed system of two launch vehicles designed to carry humans to the Moon. It evolved from the Crew Launch Vehicle (CLV) described in the Exploration Systems Architecture Study (ESAS). CLV was intended to serve two purposes. One, it was to carry the Orion spacecraft, then known as the CEV, to orbit where it would rendezvous with other components of the Earth-Moon stack. The other was to service the International Space Station (ISS). Other architectures were considered, including a dual launch of two man-rated heavy-lift vehicles (HLVs). However, one of the advantages of separating the CLV from the HLV was that the CLV could be fielded early enough to support the ISS. When this architecture was chosen, the CLV was to begin operations in 2011. It would run “taxi service” to the ISS until the HLV became available, at which point tests for the Moon mission would begin.

The CLV design selected by ESAS has other positive aspects. The study estimated that the loss of crew (LOC) risk would be roughly 1 every 2000 flights, far better than Space Shuttle demonstrated LOC. However, according to Augustine panel member Jeff Greason, “PRAs grossly overstate the reliability of an as-yet unflown system”, meaning that the CLV LOC number does not include unpredictable factors such as human error or design error. The CLV was also based on direct Shuttle-heritage hardware, including a four segment solid rocket booster (SRB) and a Space Shuttle Main Engine (SSME). This would significantly reduce development cost and risk.

The CLV eventually became Ares I. Its development would be lead by NASA, in the interest of accelerating the schedule and of reconstituting NASA’s rocket design capability. This capability had been lost in the decades after Space Shuttle development was completed. In the United States, the only organizations with orbital rocket design teams at that point were United Launch Alliance (ULA), Orbital Sciences, and SpaceX. Several changes were made to the CLV design. The CLV second stage needed an air-start capability, meaning that ignition had to be initiated by the second stage and not by ground control. Modifying SSME to be both air-startable and disposable was quickly determined to be a much larger project than NASA was willing to undertake. It was replaced by the J-2X, an engine of Saturn V heritage and shared with the Ares V. J-2X underperformance compared to SSME necessitated that the second stage be shortened and the first stage be upgraded from a four segment SRB to five segments. Due to these changes and more detailed work estimates, the initial operating capability (IOC) date was moved from 2011 to 2014. Ares I would still service ISS for 1-2 years, but a “gap” appeared in NASA’s ability to launch astronauts from Shuttle retirement in 2010 until Ares I IOC in 2014. Ares I’s ability to support the ISS was still considered to be viable, due to the high likelihood that Congress would not allow ISS to be terminated in 2016, even though the projected budget did not include an extension.

Work began on Ares I with the previously mentioned changes, while Ares I-X went on a separate path. Instead of flight-testing the Ares I first stage, Ares I-X would test the four segment SRB specified for the CLV. This would still validate that a rocket with a Space Shuttle SRB for a first stage could launch successfully. Ares I-X has remained on-schedule for its first flight in 2009. The United States Air Force, responsible for range safety at Cape Canaveral, has raised a concern that vibration caused by SRB thrust oscillation will cause failures in the Ares I-X avionics. The test launch is currently scheduled for the end of October.

The Ares I development schedule is much longer than Ares I-X. Starting in 2005, it was projected to take roughly six years to complete. Changes in 2006 from CLV to Ares I raised that to eight years. The schedule was extended a year by NASA in 2007. The Aerospace Corporation performed an independent schedule assessment in 2009 and determined that the remaining development work would take seven years to complete. In the three years from 2006 to 2009, Ares I has closed on its schedule end date by one year. The Review of U.S. Human Space Flight Plans Committee found that Ares I no longer supports the ISS, because, even with an optimistic budget projection, ISS will have to be de-orbited before Ares I IOC. This restriction is due to schedule pressure caused by operating Ares I while developing Ares V. Removing one of the two major rationales for developing Ares I illustrates why a review of the Constellation program is needed at this time.

About $8 billion dollars has been invested in Ares I development as of 2009. The project has passed two major hardware milestones: the successful tests of the abort system and the test firing of the five segment SRB. A test flight of Ares I-X seems imminent, as these things go. Some technical problems threaten the development of an operating vehicle. Ares I’s payload capacity is insufficient to launch the Orion space capsule as originally designed. This has necessitated several redesigns of Orion, and may result in future delays to both Ares I and Orion. Vibration due to thrust oscillation continues to threaten both passengers and avionics. The five segment SRB test may have retired some of the risk, but thrust oscillation severity in Shuttle SRBs has historically varied widely. These problems, plus some others, were estimated by the review panel to be solvable given enough time and money.

The main proponent of the Program of Record is former NASA Administrator Michael Griffin. In his testimony to Congress, he charged that the review panel “double-counted” the schedule reserve for Ares I development, unnecessarily extending it from 2015 to 2016. Also, in his opinion, ISS funding should be decoupled from Constellation development. This would allow Ares I to service ISS during the years 2015-2020. In Griffin’s estimation, this would cost NASA roughly $15 billion above the review panel’s unconstrained projection. Griffin also notes that a dual Ares V mission would cost hundreds of millions more per mission than the Ares I + Ares V approach.

Given enough funding, Griffin’s approach could work well. Ares I has certainly retired some technical and schedule risk in three years of development. For $45 billion above the president’s budget projection, NASA could simultaneously operate two launch vehicles, service the ISS, and accomplish its Moon mission. However, a plus $45 billion budget was investigated neither by the review panel nor by Congress. Compared against other plus $30 billion options, continuing to build Ares I means the end of ISS in 2016.

Canceling Ares I does not imply that $8 billion has gone down the drain. Ares development to date has produced several benefits which may prove useful to the exploration program. First, the recently tested five segment SRB would be used in the Ares V Light design, though not in other Shuttle-derived designs. Second, Ares I development will have been a valuable learning experience for NASA and served to reconstitute a NASA orbital rocket design team. Third, it has started work on the J-2X rocket engine, which will inform future rocket designs. Fourth, the Ares I-X test will give Kennedy Space Center practice launching rockets which are not Space Shuttles.

In conclusion, choosing to continue development on Ares I is a question of the value placed on other aspects of the exploration program. The primary loss in the Program of Record is the ISS. Alternative programs would not only extend its time on orbit, they would increase utilization and improve its return on investment. Another loss is the potential for NASA to jump-start a commercial crew launch service. The other loss in the Program of Record is the technology development program. Avoiding technology development for the next two decades means that NASA cannot hope to increase the pace or duration of exploration missions, or to extend those missions beyond the Moon. If the value placed on these aspects is minimal, Ares I in the enhanced budget Program of Record is viable and appears to expose the exploration program to less development risk than the other options.

References

• “Launch Vehicles and Earth Departure Stages“. Exploration Systems Architecture Study. National Aeronautics and Space Administration. November 2005.
• “Multi-Program Integrated Milestones“. National Aeronautics and Space Administration. Q3 2008.
• “Vibration Analysis Delays Ares I-X Stacking“. Aviation Week. July 6, 2009.
• “Summary Report“. Review of US Human Space Flight Plans Committee. September 8, 2009.
• “ Mike Griffin Lashes Out at The Augustine Committee via Email“. SpaceRef.com. September 10, 2009.

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10. DIRECT

DIRECT is NASA’s last chance to retain its own crew launch system in the wake of Space Shuttle retirement. It’s a derivative of the Space Shuttle External Tank and Solid Rocket Boosters, combined with the Orion space capsule. Given how many pieces of this rocket are flying today, it seems possible to get this operational relatively quickly. Unfortunately, the DIRECT team made some strategic blunders while trying to get their idea accepted, and then came off as paranoid when they presented their plan to the Augustine Committee. Then NASA came up with their sidemount HLV, which is conceptually similar but totally inadequate for launching astronauts. The committee was forced, for lack of time and resources, to bin them together, losing the crew capability in the process. Nice job, everyone.

9. Polywell fusion

Wishful thinking, or our best shot at getting off this planet? We can pursue cheap rockets, reusable rockets, and extraterrestrial resources all we want, but we’re always restrained by the limited amount of energy contained in our chemical propellants and converted by our solar panels. If we want to start talking about moving thousands of people permanently into space, we need something better. Nuclear fission has proved too difficult and dangerous for the amount of extra energy available. The best candidate on the drawing boards is being pursued by the U.S. Navy as a power source for their ships. It’s small, produces unbelievable amounts of energy from small amounts of fuel, and generates no dangerous radiation. The late inventor, Dr. Robert Bussard, also known for the Bussard ramjet, intended it to power spaceships. The team recently received another $8 million in funding and says we’ll know in a few years if their theories pan out. If they do, expect to visit the Moon in your lifetime.

8. X-Prizes

Nothing gets people excited about space like competition involving lots of fire. It’s what made Apollo work, after all. The first big space prize was the Ansari X-Prize, which was won by Burt Rutan in 2004 when he built his own plane that was flown into space by Mike Melville and Brian Binnie. More recently, Armadillo Aerospace took first prizes in both level 1 and 2 of the Lunar Lander Competition. These, and the teams they are competing against, are making important progress in space technology, in exchange for a rather small amount of public and private money. Next up is the Google Lunar X-Prize, where stuff actually lands on the Moon.

7. Moving asteroids

It seems impossible, but physically it can be done with current technology. Specifically Near Earth Objects (NEOs) in the 500 meter range, the kind that might not kill you if it hit the Earth but would certainly make your life miserable. If there’s one thing the government must do in outer space, it’s this. What makes it possible is that with precise tracking and a lot of warning time, we don’t have to move the rock very far at all to prevent a disaster. Asteroid 99942 Apophis will likely be tagged with a beacon in the near future.

6. Inflatable space stations

It seems silly, but balloons are a useful construction method in outer space, as long as they are made out of a material that can withstand the extreme environment. Dr. Werner von Braun first suggested this for his wheel space station back in the 1950s, but he didn’t have the technology to make it work. More recently NASA investigated building an inflatable module for the ISS, but cancelled it as being too risky. Hotel chain owner Robert Bigelow licensed the technology from NASA to use to build his own space stations, and has launched two prototypes. Now NASA wants to buy space station modules from him.

5. COTS

A new concept in space systems development. Instead of paying someone extra money if they take longer to build something, you just pay them when they deliver the thing you want. The former is called cost-plus contracts, and it’s the reason everything involving outer space in the United States costs so much money. Want to know why NASA struggles to explain exactly what you got out of all the money you sent them last year? This is why. Luckily someone came up with a system that makes sense, and it’s working marvelously in a program called COTS, which purchases cargo transportation to ISS.

4. VASIMR

Two types of rocket engines power today’s spacecraft. One is the chemical rocket, which produces a lot of thrust but uses a lot of fuel in the process, so much that its tanks are usually empty after firing for 10 minutes. The other is the ion drive, which produces a tiny amount of thrust but uses fuel much more efficiently. It can run for months or years. Both have their uses, but what we really need is an engine that can produce a lot of thrust but use less fuel. VASIMR, under development, is that engine. One may be installed on the ISS in the next decade to help maintain its orbit.

3. Flexible Path

This one came out of the Augustine Committee that I’ve been following the past couple of months. Their Flexible Path architecture for human spaceflight involves bypassing the surfaces of the Moon and Mars, and instead takes off across the Solar System in space capsules. The surfaces of many objects would still be accessible, like the asteroids and the moons of Mars. Landing on Mars isn’t so difficult, it’s the getting off that’s nearly impossible. You’d need a small colony in place just to operate the launch site, and that’s not going to happen any time soon. Taking the Flexible Path is like picking the low-hanging fruit, and staying out of gravity wells will be a primary goal of our spacefaring descendants anyway.

2. Space tourism

We saw a sea change in the last decade in human spaceflight. Private citizens flew into outer space, before a realm occupied solely by government employees. Suddenly seats going into orbit had a price tag on them. This created a market, and healthy markets breed efficiency. This is the market: tens of passengers per year at $10 million per seat, hundreds at $1 million per seat, and so on. We can make it to the thousands per year, and space tourism got the ball rolling.

1. Propellant depots

Something was missing from the Apollo missions, and it was this: when astronauts went the Moon, they found nothing to help them along the way. The thing space explorers need more than anything else is rocket fuel. When we send humans into the Solar System again, we can pre-place caches of rocket fuel at strategic points, called Lagrange points. We might even leave a space capsule at the depot, so we don’t have to carry it all the way to the Moon or Mars. Developing this ability might even mean we can make it back to the Moon without developing a new super-heavy rocket booster like the Saturn V, and that would really move up the schedule for Solar System exploration.

If you enjoyed this article, you’ll like the next one even better: Ten Worst New Space Ideas.

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Ares V Light is a simplification of the Ares V design, which itself is a derivation of the Cargo Launch Vehicle (CaLV) described in the 2005 Exploration Systems Architecture Study (ESAS) report. ESAS considered several combinations of existing hardware and extensions to that hardware that were considered low-risk. CaLV comprised a Space Shuttle External Tank (ET)-sized core powered by five Space Shuttle Main Engines (SSMEs) and two five-segment Space Shuttle Solid Rocket Boosters (SRBs). The SSMEs would be thrown away on every flight. CaLV would send about 55 metric tons (mT) to a trans-lunar injection (TLI).

Ares V Light and Ares V differ outwardly only in the number of segments in each SRB

CaLV eventually was refined into the Ares V design. Ares V was modified in several ways from the CaLV in order to increase payload and reduce per-flight cost. In particular it uses expendable RS-68B engines derived from the Delta IV, and it extended the SRBs to 5.5 segments. The payload capacity of Ares V is an impressive 159 mT to LEO and 71 mT to TLI. With these upgrades, Ares V deviates significantly from the Ares I components that it was intended to share. Also, it requires the development of a new SRB design and a new LOX/LH2 engine variant.

Ares V Light is closer to the original CaLV design in that it maintains the original 5 segment SRB. Another difference is that it trades the advanced RS-68B for the RS-68A, which is nearing operational capability on the Delta IV. Payload capacity is reduced to 143 mT. This limits it to sending the Orion space capsule to the Moon or the Altair lander, but not both at the same time. Thus, a mission to the lunar surface would require two launches of Ares V Light instead of one Ares I and one Ares V. An additional crew launch aboard a commercial vehicle may be required for this mission if Ares V Light is not man-rated.

Ares V Light has several advantages over the baseline Ares I + Ares V configuration. Primarily, it requires the development and operation of a single NASA-owned rocket instead of two. The committee found that operating both Ares I and Ares V at the projected budget levels would consume NASA’s entire exploration budget, leaving nothing for expeditions beyond LEO. Also, Ares V Light would require less development work. The five segment SRB has been successfully tested, as have the RS-68A engines. The downsides are that it would have less lift capacity in a single launch, and that it would render moot some of the development work that has gone into Ares I. Ares V Light development is projected to finish in the early 2020s. After the Space Shuttle is retired, NASA would have no in-house space launch vehicles for more than a decade. This would extend the “gap” during which NASA would be unable to fly its astronauts by about five years over the baseline case. However, this could be mitigated by encouraging the development of commercial alternative crew launch, which the committee estimates would be ready by 2016.

The Ares V Light configuration first appeared in Bo Bejmuk’s July 29 presentation of the LEO Access subcommittee. Information about this configuration seems to have come from NASA Marshall Space Flight Center (MSFC), as Ares V Integration Manager Steve Creech referred to it in his presentation that day. Ares V Light was included in three of the seven architectures retained after the August 12 meeting, and those options were carried forward in the final report. The summary stated “of these two Ares system alternatives, the Committee finds the Ares V Lite in the dual mode the preferred reference option.”

References

• “Launch Vehicles and Earth Departure Stages“. Exploration Systems Architecture Study. National Aeronautics and Space Administration. November 2005.
• Bejmuk, Bo. “LEO Access Subgroup“. Review of US Human Space Flight Plans Committee. 29 July 2009.
• “Transcript: Constellation Architecture, Part 6b“. Review of US Human Space Flight Plans Committee. 29 July 2009.
• “Integrated Options for Human Exploration Discussion“. Review of US Human Space Flight Plans Committee. 12 August 2009.
• “Summary Report“. Review of US Human Space Flight Plans Committee. 8 September 2009.

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On top of the common recommendations, the Deep Space option remains on the table, which I think would further accelerate our expansion into the Solar System. Propellant depots also will appear in their report in some fashion. This, however, is not as critical. I have no confidence that NASA can develop a new heavy-lift launch vehicle, although side-mount comes close to credibility. Non-essentials such as propellant depots, landers, and in-situ resource utilization will be dropped eventually as NASA and Congress neuter the program like they did to the ISS.

Sadly, I think the option to upgrade EELVs to heavy-lift capacity is politically infeasible. President Obama might be willing to expend some political capital to increase the budget and succeed where Bush failed. There is no way he would put his neck out far enough to dismantle KSC. However, it was a welcome validation of the arguments I and many others have made over the past decade to hear that the fastest way into space is to get NASA out of the way.

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