XS-1: A Closer Look at the Government’s Latest — and Sanest? — Attempt to Reduce Launch Costs

Artist's conception of a nominal X-S1 vehicle. (Credit: DARPA)
Artist’s conception of a nominal X-S1 vehicle. (Credit: DARPA)

In the era of bell bottoms and Richard Nixon, there was the space shuttle.

When Ronald Reagan ruled the roost, all hope rested in the National Aerospace Plane.

During the Bill Clinton era, there were the X-33 and Venture Star.

In Barack Obama’s first term, the Air Force pursued its Reusable Booster System (RBS).

Five programs. One objective: to radically reduce the cost to orbit. More than $14 billion spent on development. And the result? A super expensive shuttle program. Four vehicles that never flew. And access to space just kept getting more expensive.

Undaunted by these previous failures, the brilliant engineers and scientists at DARPA are once again giving it  the old college try. And this time around, they believe the technology has finally caught up with the ambition of making flying into orbit a daily occurrence.

The latest program is know as the Experimental Spaceplane — or XS-1. The objective “is to demonstrate a reusable first stage launch vehicle capable of carrying and deploying an upper stage that inserts 3,000 to 5,000 lb. payloads into Low Earth Orbit (LEO), designed for less than $5M per launch for an operational system.”

The system has to be able to perform with aircraft-like operations. And demonstrate the ability to fly 10 times in 10 days. It needs to reach Mach 10 at least once. And provide the basis for next-generation launch services and “global reach hypersonic and space access aircraft.”

Credit: DARPA
Credit: DARPA

In short, it has to be able to do something no flying vehicle has been able to do. Ever. And do it at a cost and with a frequency and ease that would revolutionize access to space.

That’s all.  Easy as cake. (Pie!)

A successful program would do a great deal to help out the America’s military, which is facing increased costs for access to space and new strategic threat even as its budget gets squeezed. The costs — which are now at $3 billion per year and rising — are well demonstrated in the graphic below, which shows how expensive U.S. launch vehicles are to purchase.

Credit: DARPA

The military primarily uses the Evolved ELVs (EELVs), which include the Atlas V and Delta IV. Those rockets are highly reliable but extremely expensive.  United Launch Alliance builds both vehicles, giving it a monopoly on the launches of large payloads for the DOD, NASA and other agencies. Defense also makes use of smaller launch vehicles that include Orbital Sciences Corporation’s Minotaur and Pegasus, but they are relatively expensive for the size of the payloads they place into orbit.

SpaceX has lately begun offering the medium-lift Falcon 9 rockets for $56 million per launch. However, that rocket is not yet certified to carry defense payloads.  SpaceX’s Falcon Heavy booster, which will cost $128 million per launch, has not yet flown. So, it will be a couple of years before SpaceX can compete for DOD launches and begin to bring down costs.

Neither the EELVs nor the smaller rockets the DOD now use are competitive on the international market, meaning that ULA and Orbital must making money on a limited number of government launches per year.  That means they build a relatively small number of launch vehicles, limiting their ability to spread costs across larger orders.

With the cost of launches rising, the DOD has taken advantage of improvements in technology to build larger, more expensive satellites that last longer. The approach has resulted in a cost spiral in which expensive satellites are launched a smaller number of rockets that cost more. The cost of putting a single GPS spacecraft into orbit now runs $800 million — $500 million for the satellite and $300 million for the launch.

Credit: DARPA

But, costs are not the only considerations. Current boosters need to be ordered years in advance, and they require a considerable amount of pre-flight preparation at fixed launch sites. The military currently has no surge capability — the ability to quickly launch additional assets to respond to a crisis or replace spacecraft that have failed or been taken out by an enemy.

XS-1 Approaches
Credit: DARPA

DARPA has already launched its Airborne Launch Assist Space Access (ALASA) program, which aims to be able to put a 100 lb (45 kg) payload into low Earth orbit for $1 million. The goal is to be able to quickly launch tactical assets into space on a short time frame from any airfield in the world.

The XS-1 program is not a traditional, top-down program in which the government will determine what it wants to build and then take bids. Instead, DARPA is looking to American industry to propose their best ideas for how to meet the cost, payload and operational requirements it wants to meet.

The government has already looked at a number of reusable, off-the-shelf engines for powering the test vehicle, including SpaceX’s Merlin 1D and the AJ-26 that powers Orbital’s new Antares launch vehicle. However, DARPA is open to new engines being developed by such companies as XCOR and Ventions, LLC.

The design space for innovations in propulsion, vehicle configuration, launch and recovery operations, and structures is wide open for this project.

Credit: DARPA
Credit: DARPA

In light of the litany of failed programs over the past 40 years, you might ask why DARPA is at all optimistic that this program will work.  Their hopes rest on three pillars.

First, they believe that previous efforts were leaps too far using immature designs and technology that just wasn’t ready to fly. The results were a space shuttle that was enormously expensive and programs such as NASP and Venture Star that never flew because the technology just wasn’t there yet.

Credit: DARPA

Over the past 20 years, however, investments and research into a whole range of technologies are giving DARPA confidence that the XS-1 program can achieve its goals. There has been significant advancements in composites, engines, thermal protection and other key areas.

Third, the agency is also hoping to tap into progress in new technologies and low-cost systems that has been made by space companies such as XCOR, Stratolaunch, Scaled Composites and others.

 DARPA sees a number of markets to justify the expense of development funds. The first two are government and commercial payloads. Getting launch costs down will open up opportunities for a lot more payloads to be sent into space.

Credit: DARPA

Officials also believe an XS-1 vehicle would serve as an excellent testbed for hypersonic research.  The military is extremely interested in fielding systems that can be rapidly deployed anywhere in the world. This research has potential spin-offs for point-to-point hypersonic transports.

The XS-1 technologies can be scaled up for a variety of other uses, the defense agency believes.

Credit: DARPA

DARPA held a proposers day even on Nov. 6 that was attended by more than 120 industry representatives. Proposals are due on Jan. 16, with contracts signed and initial trade studies commencing in the second quarter of next year. If all goes well, flight tests could begin in late 2017, with an orbital satellite launch in the third quarter of 2018.

Credit: DARPA
Credit: DARPA

The schedule assumes that the project can be executed along the lines envisioned, that it receives sufficient funding for the rest of Obama’s term, and the new administration that takes office in January 2017 doesn’t decide to cancel the whole thing. If the program is seriously behind schedule, over budget or has run into intractable technical problems by then, the XS-1 will likely join the litany of failed cheap access of projects that stretches back 40 years.