Space Access LLC RLVs

FutureSpaceTourist

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Space Access LLC was originally formed in 1994. One thing a bit different about their proposed RLVs is that they didn't only use conventional rocket engines, but instead an 'ejector ramjet' that uses liquid hydrogen fuel but oxygen from the atmosphere. Space Access claimed that the ejector ramjet is seven times more efficient than a rocket engine because the vehicle doesn’t have to carry its own oxidizer.

Here's a brief video of a ramjet test:

http://www.youtube.com/watch?v=DPZb88c1vXU

In the 90s Space Access proposed an RLV called simply the SA-1. Not many images of the SA-1 seem to be available (please contradict me if you have some!). A couple of artworks attached, apologies for the relatively poor reproduction.

The following summary of the SA-1 comes from the 2001 RLV report published by the FAA.

[quote author=FAA 2001 RLV summary]
SPACE ACCESS, LLC, is developing the SA-1, an unmanned spaceplane that uses a hybrid propulsion system and one or two rocket-powered upper stages to deliver a full range of payloads to LEO or GTO.

The entire SA-1 launch system is designed to be compliant with commercial aerospace worthiness standards, the equivalent of airworthiness standards for transport aircraft imposed by the FAA. The propulsion system for the system’s first stage, the “aerospacecraft,” is based on a proprietary modification by SPACE ACCESS to the ramjet engine design that has been in operation since the early 1960s. The modification to the engines allows the ramjets to operate at both subsonic and supersonic speeds (ramjets normally only operate above Mach 2). One of the company’s subcontractors, Kaiser Marquardt, has tested elements of the propulsion system, and SPACE ACCESS has worked with the Air Force Research Laboratory since September 1995 under a Cooperative Research and Development Agreement to review the SA-1 aeromechanics and the “ejector” ramjet propulsion system. As of March 1998, SPACE ACCESS had wind-tunnel tested the ejector ramjet engine at all of the altitudes and speeds of the SA-1’s planned flight profile.

The SA-1 vehicle will take off horizontally from a conventional runway, using a mixture of air and liquid hydrogen to power its ejector ramjet engines. As the aerospacecraft climbs and accelerates and reaches the limits of the atmosphere, it will gradually transition from ramjets to liquid rocket propulsion in order to reach its final altitude and speed of over 100 kilometers and Mach 9. The aerospacecraft will then deploy an upper stage with its satellite payload and return to land on a conventional runway. The SA-1 will carry a single, rocket-powered upper stage for LEO missions and two upper stages for GTO. After deploying the satellite payload, the upper stage will de-orbit and return to land horizontally on the same runway.

The SA-1 vehicle will be able to launch payloads of over 5,200 kilograms to GTO. Although SPACE ACCESS intends to pursue deployment of commercial geostationary satellites as its primary market, the SA-1 will also have a capability of deploying well over 15,000 kilograms to LEO as well. The SA-1’s significant payload capability and reliability, derived from being designed in compliance with rigorous transport aircraft-based standards, will also make the SA-1 well-suited for conducting resupply missions to the ISS.

In 1998, while working with NASA on a Space Transportation Architecture Study program contract, SPACE ACCESS began to study the concept of developing a crewed version of the second stage, which would give the SA-1 the capability to provide human access to space. In 2000, NASA awarded SPACE ACCESS a contract to develop Commercial Aerospace Worthiness Standards to be used by commercial RLV companies to obtain approval from the FAA to carry passengers for hire on commercial RLVs.

In cooperation with the State of California, SPACE ACCESS is now conducting tests of its proprietary integral hot structure which is based on the use of FAA-certified structural materials. SPACE ACCESS currently plans to expand its test program over the next several years to include avionics and full-scale propulsion hardware as well.
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In December 2007 Space Access announced plans for a suborbital space tourism vehicle Skyhopper. See press release details in http://www.prnewswire.com/news-releases/space-accessr-offers-major-expansion-of-space-tourism-beginning-january-2008-58824612.html.

Interesting claim from that release:

Over the past 13 years, SPACE ACCESS has developed the use of hydrogen-fueled ramjet propulsion system, structural and thermal protection materials, and innovative aerodynamic design that allow a completely different approach to space travel. These technologies have resulted in the award of 26 patents, with 9 additional patents pending.

Some basic details on Skyhopper (and the attached image) come from the FAA's 2009 U.S. commercial space transportation report:.

[quote author=FAA 2009 U.S. Commercial Space Transportation report]
The vehicle would take off and land horizontally on a conventional runway, and use ejector ramjet engines with liquid hydrogen fuel—as opposed to conventional rocket engines—to reach suborbital altitudes. SPACE ACCESS anticipates Skyhopper™ will reach speeds of up to Mach 5 and altitudes in excess of 100 kilometers (62 miles).

The company plans on building up to eight Skyhopper™ vehicles and operate up to 15 flights per day. Suborbital flight operations are scheduled to begin in 2013 from facilities to be developed in Florida and Texas. Orbital flights, using a variant of Skyhopper™, are projected to begin as soon as 2016. In 2008, SPACE ACCESS announced plans to construct a fleet of up to eight vehicles for the suborbital flights.
[/quote]

However, there's nothing in the current - 2010 - FAA report and the company's website www.spaceaccess.com no longer seems to be working.

I forgot to mention in my previous post that several Space Access engineers previously worked on the NASP. Might explain the interest in the propulsion technology and maybe some other design features?

Space Access attempted an unusual way to raise some funds - by offering 3-day stays at an "exclusive luxury resort located on the island of Key Largo, Florida". A few details on that is at http://www.xtraordinaryadventures.com/news.html.
 

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Thanks to Randy, SA-1 patent info below (cross-posted here so Space Access info all togther):

RanulfC said:
As an FYI the Space Access ERJ patent number is #6,786,040 B2 and the patent number of their vehicle is 6,193,187 B1 (Available from your favorite patent look-up-link :) )

Once I've had a chance to read it, I'll post a summary of any interesting details!
 
The patent stretches to 25 pages and contains quite a lot of material - so worth a read!

First attached picture shows the flight profile for a 3 stage mission - note that the 2nd and 3rd stages are also fully reusable (although expendable stages could also be used). To quote from the patent: "All the stages have the basic aerodynamic vehicle elements of a fuselage, wings, and tail, with the incorporation of control surfaces to supply lift, stability and control."

IMHO one of the interesting things about the SA-1 is how the 2nd/3rd stages and payload are carried internally within the 1st stage spaceplane, via a nose faring that opens and closes. Second attached picture shows a cut-away view and third picture a loading view.
 

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An article on Space Access LLC. Sorry for the lousy sscreenshots.

Popular Science, June 1999

https://books.google.com/books?id=gJfxBTKptj0C&pg=PA76&lpg=PA76&dq=space+access+aerospacecraft&source=bl&ots=SyBh0G81bG&sig=UyrvLdeG0-oHoR-1HVcbNtB_n-s&hl=en&sa=X&ved=2ahUKEwjj6ZL67eDbAhUEi6wKHfO4AaMQ6AEwAnoECAQQAQ#v=onepage&q=space%20access%20aerospacecraft&f=true
 

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some papers about ejector ramjet

Space Access Patent
http://www.freepatentsonline.com/6786040.html

1975 paper about testing one with UDMH as fuel
http://www.dtic.mil/dtic/tr/fulltext/u2/a016430.pdf

1997 paper "Evaluation of an Ejector Ramjet Based Propulsion System for Air-Breathing Hypersonic Flight"
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19970017381.pdf

Patents
https://patents.google.com/patent/US5205119
https://patents.google.com/patent/US5946904
 

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