The Sabre engine could take a plane to five times the speed of sound and an altitude of 25 km, about 20 percent of the speed and altitude needed to reach orbit. For space access, the engines would then switch to rocket mode to do the remaining 80 percent.
Reaction Engines believes Sabre is the only engine of its kind in development and the company now needs to raise about 250 million pounds ($400 million) to fund the next three-year development phase in which it plans to build a small-scale version of the complete engine.
The engine technology could win a healthy chunk of four key markets together worth $112 billion (69 billion pounds) a year, including space access, hypersonic air travel, and modified jet engines that use the heat exchanger to save fuel.
The fourth market is unrelated to aerospace. Reaction Engines believes the technology could also be used to raise the efficiency of so-called multistage flash desalination plants by 15 percent.
The heat exchanger technology could also be incorporated into a new jet engine design that could cut 5 to 10 percent – or $10 (6.25 pounds)-20 billion – off airline fuel bills.
It is likely that the Spaceplane will take over 10 years to develop and commercial hypersonic space travel will also take many years to certify for passengers. The desalination market could be first and then modifying engines for fuel efficiency would also take a few years to get to market but would likely be before the more extreme spaceplane and hypersonic planes.
Spacex is competing to develop fully reusable rockets and will likely get to market first. However, Skylon spaceplanes and hypersonic planes would revolutionize a lot of other markets and applications.
Military applications (missiles) and unmanned vehicles would arrive before passenger applications.
Skylon is also more compatible with beam powered boosting to orbit. A Proposal by Keith Henson described in an interview with Nextbigfuture.
Lasers heating hydrogen could result in exhaust velocities as high as 10 kilometers per second, even higher than the nuclear reactors did.
Running the expensive lasers at close to full time sets the flight rate. They take 16 minutes to accelerate the payload to geosynchronous transfer orbit and 4 minutes to circularize the payload orbit at GEO.
Three flights per hour delivers 60 tons per hour to GEO. That is 25,000 launches per year, which also gets the cost per flight down. At 72 flights a day and a two day turnaround plus spares it would take perhaps 200 Skylons It sounds like a lot, but a Skylon should not cost any more than a Boeing 777 ($250 M) and there are nearly a thousand of those in service.
The European Space Agency appears to have signed off on the tests and will be allocating some portion of their new space budget for follow on projects related to the Skylon spaceplane which is enabled by the pre-cooler.
Critical tests have been successfully completed on the key technology for SABRE, an engine which will enable aircraft to reach the opposite side of the world in under 4 hours, or to fly directly into orbit and return in a single stage, taking off and landing on a runway.
SABRE, an air-breathing rocket engine, utilises both jet turbine and rocket technology. Its innovative pre-cooler technology is designed to cool the incoming airstream from over 1,000 degrees Celsius to minus 150 degrees celsius in less than 1/100th of a second (six times faster than the blink of an eye) without blocking with frost. The recent tests have proven the cooling technology to be frost-free at the crucial low temperature of -150 degrees celsius.
The European Space Agency (ESA) has evaluated the SABRE engine’s pre-cooler heat exchanger on behalf of the UK Space Agency, and has given official validation to the test results.
Reaction Engines heat exchangers are 100 times lighter than current technology allowing them to be used in weight-critical aerospace applications. This is achieved through the use of extremely thin walls to separate the hot and cold fluids within the heat exchangers, coupled with advanced manufacturing techniques needed to bond these fine structures whilst maintaining their strength, durability and low weight.
For example, REL has made the tube walls for its Pre-cooler as thin as possible – in our most recent demonstration the tube walls were only 27 microns thick but are bonded together to resist pressures greater than 150 bar – that’s 150 times greater than atmospheric pressure at temperatures ranging from over 1,000°C to less than minus 150°C .
* Over 50 km of heat exchanger tubing for a weight penalty of less than 50kg
* Heat exchanger tube wall thickness less than 30 microns (less than the diameter of a human hair)
* Incoming airstream to be cooled to -150 °C in less than 20 milliseconds (faster
than the blink of an eye)
* No frost formation during low temperature operation
Finetubes – each engine uses over 2000km of tubing which has to be extremely thin to minimise weight and to act effectively as a heat exchanger, but also very strong because of the heat, pressure and forces involved. Fine Tubes specially designed a high pressure tube for this pre-cooler system with a wall thickness of just 40 microns, whilst maintaining structural integrity at extreme conditions