Aerospike Rocket Engines- You learn something new every day.

So, yesterday I heard that a new startup in Texas was looking to build a launcher for small satellites. The company is named Firefly, and of course, a quick google search found mostly pics of Serenity and Mal Reynolds. But one thing caught my eye, was a reference to aerospike engines, which the company plans to use. That lead to the question, what the hell is an aerospike engine?

You’re familiar with a liquid fueled rocket engine, right? Let’s look  at a typical engine. The is the RS-25, a derivative of the Shuttle Main Engine intended for the future SLS platform.

Pumps mix fuel and oxidizer in a combustion chamber that then flows out the bell. Simple enough.

Aerospike engines kinda turn the bell idea upside down. The flame exhaust goes outside of a wedge, and uses ambient air pressure to shape the plume.

Confused? So was I.


In spite of extensive testing and several developmental models, the aerospike has never flown to space. Whether Firefly Systems changes that remains to be seen.

Bring The HEAT Podcast

Join Roamy, Spill and me, your host, XBrad for a discussion of space exploration, the F-35 vs. the F-16, and Cyberwarfare.

Other than for some reason the recording dropping the last 10 minutes of Roamy’s segment, it mostly went well. No animals were harmed in the making of this podcast.

You can stream the podcast here.

Continue reading “Bring The HEAT Podcast”

X-37B Launch Video, and A Co-author quoted in the New York Times

Yesterday the Air Force hush-hush X-37B space plane successfully launched from Cape Canaveral.


In addition to whatever the Air Force has the X-37B doing, they allowed NASA to piggy-back an experiment aboard.

NASA is also taking advantage of this X-37B flight to test how almost 100 materials react to the harsh conditions of space, like the barrage of radiation and swings of temperature the craft will experience while passing between the day and night sides of the Earth for at least 200 days.

“It’s just sitting there and letting the environment hit it,” said Miria Finckenor, a materials engineer at NASA’s Marshall Space Flight Center in Huntsville, Ala. She is the principal investigator for the experiment, which is housed in the space plane’s cargo bay.

The materials to be tested include thermal coatings to keep spacecraft components within a certain range of temperatures, clear materials under consideration for lighter windows on NASA’s Orion crew capsule and ink to make sure that markings on parts do not fade away.

NASA previously tested more than 4,000 samples outside the International Space Station, but it is difficult to carve out time during spacewalks to set up and retrieve the experiments. “This opportunity presented itself, and we just needed to take advantage of it,” Ms. Finckenor said.

I’m just a simple grunt. Would you believe that I actually know three, count ‘em, three honest to goodness rocket scientists?


Sounds like my in-house Rocket Scientist/Super Model is busy this afternoon, so I’ll put up the space updates.

First, the mysterious X-37B is also taking along a not so hush-hush experiment. The METIS is similar to other tests such as LDF and MISSE on the reaction of various materials exposed to space for varying durations.

Building on more than a decade of data from International Space Station (ISS) research, NASA is expanding its materials science research by flying an experiment on the U.S. Air Force X-37B space plane.

By flying the Materials Exposure and Technology Innovation in Space (METIS) investigation on the X-37B, materials scientists have the opportunity to expose almost 100 different materials samples to the space environment for more than 200 days. METIS is building on data acquired during the Materials on International Space Station Experiment (MISSE), which flew more than 4,000 samples in space from 2001 to 2013.

“By exposing materials to space and returning the samples to Earth, we gain valuable data about how the materials hold up in the environment in which they will have to operate,” said Miria Finckenor, the co-investigator on the MISSE experiment and principal investigator for METIS at NASA’s Marshall Space Flight Center in Huntsville, Alabama. “Spacecraft designers can use this information to choose the best material for specific applications, such as thermal protection or antennas or any other space hardware.”

We’re curious about something not mentioned in the release. How different is the orbit of the X-37B from the ISS, in terms of both altitude and inclination, and what effects might that have on the exposed materials?

Next up, Space-X. We’ve all enjoyed watching Elon Musk’s Falcon 9 attempt to safely land after orbital launch missions. Looks like they’ll try again in June. But the other major endeavor underway at Space-X is to crew certify a manned spacecraft. And one of the key tests for that is the pad abort. We’ve all seen the escape tower atop Mercury and Apollo capsules. Space-X uses a rather different approach with their manned variant of the Dragon spacecraft.


That’s an unmanned test, but I’m thinking Space-X could make some money selling that as a carnival ride.

Falcon 9 Launch Successful, Recovery Not So Much

By happenstance, we were up late last night, and happened to click on the live feed of the Space-X Falcon 9 launch live feed at almost exactly T-1 minute. The launch was nominal, and I watched all the way to solar panel deployment. In about two days, the Dragon capsule will rendezvous with the International Space Station, and deliver its cargo. So far, so good.


The radical part of the Falcon 9 program is the attempt to recover the first stage of the rocket. Rather than simply falling away as most rockets do, the Falcon 9 is intended to make a maneuver to a reentry to a planned point, use its motor to slow down, deploy landing legs, and land on a barge. Recovering the stage means the expensive part of the launch, the actual rocket motors, can be reused, greatly decreasing the cost of launching a pound of payload to orbit.

Image: Launch profile

Graphic by Jon Ross via NBC News.

Space-X had tried the maneuver portion of the reentry on previous launches. This morning was the first attempt to actually land the rocket. An unmanned barge serving as a landing platform was deployed off the Atlantic coast. Unfortunately, the rocket landed hard per Space-X head honcho Elon Musk, and recovery failed.

Apparently, the stage ran out of hydraulic fluid just prior to touchdown, causing a loss of control.


So about 99% of the mission went well. I think that’s a pretty good record, considering the complexity of what they’re attempting.

Orion poised to fly December 4th.

NASA’s Orion space vehicle is scheduled to make its first (unmanned) flight on December 4th.  Like most first flights, it’s objectives are fairly modest. Toss it up, make a couple orbits, come back down.  The one really aggressive move it will be making is that the orbits will be highly elliptical, with a maximum altitude of about 3,600 miles. That the highest orbit for a man rated vehicle in about 40 years. 

Why do this? Because Orion is not simply designed for low earth orbit, but rather for deep space exploration, potentially lunar or even Mars orbital missions. When you return from lunar flight, the reentry speed is much, much greater than from simple low earth orbit.

Not only will Orion use its power to achieve a higher orbit, it will use its engines to artificially accelerate to mimic that higher reentry speed.  A similar test was done during the Apollo program.

Here’s a look at the first quarter 2014 progress report.


Outstanding Engineering in the development of the Apollo Program Lunar Lander

The Apollo program that lead to the landings on the moon was a stunning engineering and program management feat. It simply boggles the mind the complexity of the mission, and the countless details that went into the development of the hardware, the software* and techniques and procedures that lead to Neil Armstrong’s one small step for man.

In some ways, the most complicated piece of equipment on the entire Saturn V/Apollo stack was the Lunar Module, or LM. Designed and built by Grumman, it was America’s first true spacecraft, in that it would never fly through the atmosphere, instead only in space. Without the need for aerodynamics, it had a truly unusual appearance, sometimes leading it to be called “the bug” or “the spider.” It was a two stage rocket that had to be capable of autonomous navigation from lunar orbit to the surface. It also had to serve as a base camp for astronauts for up to 72 hours, and then it had to be capable of ascending from the moon’s surface to lunar orbit and again rendezvousing with the Command Service Module under its own navigation.  It had to have its own power supply, be able to operate both in a shirt sleeve environment for the crew as well as depressurized and open to the vacuum of the moon’s surface. It had not one, but two hatches, to allow both for docking with the CSM, and to allow the astronauts to explore the surface of the moon. It was also the largest manned spacecraft built at the time.

It was, incredibly, designed well before anyone knew if rendezvous in low earth orbit was technically feasible, let alone in lunar orbit.

  Grumman, in close cooperation with North American Aviation and NASA built this incredible craft. I’m sure you’ve all seen the movie Apollo 13 where the LM served as a lifeboat to return the crew safely to home, stressing the LM in ways it was never intended to be used. To say that the engineers of Grumman built an incredible ship is an understatement.  Some of the finest engineering talent in the world focused on getting the LM just right.

Incredibly, well into the development of the LM, with most of the configuration well established, and production ready to begin, no one ever gave serious consideration to how the astronauts were supposed to get down from the LM to the lunar surface, and back inside after hopping around the moon.

Lander no ladder

Yes. That’s an astronaut holding a knotted rope. No ladder. Grumman and NASA actually even looked at a complicated block and tackle system by which astronauts would hoist themselves down and up. It took a while before it occurred to anyone to simply fasten a ladder from which Neil and 11 others could make a great leap for mankind.


*During the development of Apollo, when the engineers spoke of software, they actually generally meant the flight rules, switchology, and cockpit procedures the astronauts would use on the hardware. Software was already coined as a term for computer code in other areas, but doesn’t appear to have been in vogue in the program office for computer programming.

Meeting the Challenge: The Hexagon KH-9 Reconnaissance Satellite

A component overview of the Hexagon System.
A component overview of the Hexagon System.

The CIA declassified portions of it’s KH-9 Hexagon imaging satellite in 2011. Hexagon was first deployed into space in 1971. Between 1977 and 1986 Hexagon performed 19 missions, imaging 877 million square miles of the Earth’s surface. The KH-9 was also the last and largest imaging satellite to return it’s photographic film to earth.

KH-9 being assembled by Lockheed.
KH-9 being assembled by Lockheed.

Hexagon was desgined to replace the Corona series imaging spacecraft:

The KH-9 was originally conceived in the early 1960s as a replacement for the Corona search satellites. The goal was to search large areas of the earth with a medium resolution camera. The KH-9 carried two main cameras, although a mapping camera was also carried on several missions. The photographic film from the cameras was sent to recoverable re-entry vehicles and returned to Earth, where the capsules were caught in mid-air by an aircraft. Four re-entry vehicles were carried on most missions, with a fifth added for missions that included a mapping camera.

Between September 1966 and July 1967, the contractors for the Hexagon subsystems were selected. LMSC was awarded the contract for the Satellite Basic Assembly (SBA), Perkin Elmer for the primary Sensor Subsystem (SS), McDonnell for the Reentry Vehicle (RV), RCA Astro-Electronics Division for the Film Take Up system, and Itek for the Stellar Index camera (SI). Integration and ground-testing of Satellite Vehicle 1 (SV-1) was completed in May 1971, and it was subsequently shipped to Vandenberg Air Force Base in a 70 ft container. Ultimately, four generations (“blocks”) of KH-9 Hexagon reconnaissance satellites were developed. KH9-7 (1207) was the first to fly a Block-II panoramic camera and SBA. Block-III (vehicles 13 to 18) included upgrades to electrical distribution and batteries. Two added tanks with ullage control for the Orbit Adjust System (OAS) and new thrusters for the Reaction Control System (RCS) served to increase KH-9’s operational lifetime. In addition the nitrogen supply for the film transport system and the camera vessel was increased. Block-IV was equipped with an extended command system using plated wire memory.[9] In the mid 1970s, over 1000 people in the Danbury, Connecticut area worked on the secret project.[10]

A reentry vehicle from the first Hexagon satellite sank to 16,000 feet below the Pacific Ocean after its parachute failed. The USS Trieste II (DSV-1) retrieved its payload in April 1972 after a lengthy search but the film disintegrated due to the nine months underwater, leaving no usable photographs.[11]

Over the duration of the program the lifetime of the individual satellites increased steadily. The final KH-9 operated for up to 275 days. Different versions of the satellite varied in mass; most weighed 11,400 kg or 13,300 kg.

I suggest going through the Hexagon Wikipedia page as is there are some very interesting photos of the different components of the spacecraft.


In 2013, Phil Pressel wrote the definitive guide to Hexagon called: Meeting the Challenge: The Hexagon Reconnaissance Satellite. From the Amazon book description;

Meeting the Challenge: The Hexagon Reconnaissance Satellite is the recently declassified story of the design, development, production, and operation of the Hexagon KH-9 reconnaissance satellite. It provided invaluable photographic intelligence to the United States government, and it stands as one of the most complicated systems ever put into space. In 1965 CIA Director John McCone issued the call for a satellite with unparalleled technical requirements that could visually map most of the landmass of the earth, photograph selected areas of interest, and return the resulting film safely to Earth. Developed by the Perkin-Elmer Corporation and operated between 1971 and 1986 Hexagon was the last film-based orbiting photo-reconnaissance satellite. This engineering marvel features the following achievements: the world’s largest spherical thermal vacuum chamber used to test the system; the development and use of new and sophisticated electronics, such as LED’s and brushless motors; the ability to precisely control the synchronization of film traveling at up to 200 inches per second at the focal plane, on a rotating camera, mounted in a moving vehicle and focused on a moving earth; sixty miles of film used on each mission; and, stereo photography of the entire surface of the earth. When film captured by the satellite was sent back to earth it launched in a film-return capsule which was snagged by an aircraft as it parachuted downward upon reentering the earth’s atmosphere. In 1972 a film bucket containing sensitive images sank to the bottom of the Pacific Ocean, resulting in a daring rescue three miles underwater by the U.S. Navy’s submergence vehicle Trieste II. Featuring both technical details and historical anecdotes, former Perkin-Elmer engineer Phil Pressel has written the definitive account of this important chapter in U.S. intelligence and aerospace history.

Seems like an interesting book and as such Mr. Pressel has done quite a few media interviews. I recently watched this one from the International Spy Museum in Washington DC:


As Mr. Pressel mentioned in the interview, you can view the KH-9 Hexagon at the National Museum of the USAF. I do recall seeing it there but being rather time limited I didn’t quite have an appreciation for exactly what I was looking at. I look at the satellite with a guide and to our amusement we noticed a piece of plywood acting as a bracing member on the airframe (granted the KH-9 there is a “mockup” used to troubleshoot problems the real satellites may be having in space).

The KH-9 Hexagon as display in the Cold War Gallery at the National Museum of the USAF.
The KH-9 Hexagon as display in the Cold War Gallery at the National Museum of the USAF.