SpaceX Joins in the Long History of Catching Stuff from Space

On February 22nd, a Falcon 9 rocket lifted off from Vandenberg Air Force Base in California and successfully delivered into orbit an Earth-observation satellite operated by the Spanish company Hisdesat. Compared to the media coverage received by the launch of the Tesla-laden Falcon Heavy earlier in the month, this mission got very little attention. But that’s hardly surprising. With respect to Hisdesat, the payload this time around was not terribly exciting, and even the normally dramatic landing of the Falcon 9’s first stage was skipped in favor of simply allowing the booster to crash into the ocean.

As far as SpaceX launches go, this one was about as low-key as they come. It wouldn’t be a surprise if this is the first time some readers are even hearing about it. But while it didn’t invoke the same media circus as the images of a spacesuit-wearing mannequin traveling into deep space, there was still a historic “first” performed during this mission.

In an effort to increase the re-usability of the Falcon 9 booster, SpaceX attempted to catch the payload fairing (essentially a large protective nose cone) with a huge net as it fell from space. The most interesting thing about this new chapter in the quest for a fully reusable rocket system is that while SpaceX is generally considered to be pioneers in the world of bringing hardware back from space, this particular trick dates all the way back to the 1960’s.

An Extravagant Necessity

At first blush using a net to catch huge, falling objects sounds preposterous — like something out of Wile E. Coyote‘s bag of tricks. But remember this is a company that has made a name for itself largely based on being able to land rockets on their tails Buck Rogers style. It’s fair to say that SpaceX is not a company overly burdened by the status quo.

As comical as the idea might seem, the logic is sound. Due to the downrange distance at which the fairing is released, it has to come down in the ocean. But even if the fairing could be gently lowered into the ocean with parachutes, it contains active components (thrusters, avionics, parachutes, etc) which would need to be protected from water. But more importantly, the very construction of the fairing makes water landings a dicey proposition. It’s made of an aluminum honeycomb sandwiched between layers of carbon fiber; reliably waterproofing such a structure, to say nothing of draining water out of it in the event the waterproofing failed, would be difficult to say the least.

Falcon 9 fairing floating in the ocean

This leads us to an inescapable conclusion: if the fairing can’t be allowed to touch the water, the only option left is to catch it while it’s still in the air.

On this attempt to catch the fairing, SpaceX failed. But only just. Elon Musk reports that the fairing touched down in the ocean only “a few hundred meters” from the ship-mounted net. Not bad for a first attempt, and Elon believes that slowing the fairing down a bit more by way of a larger parachute should give them enough time to get the ship into position.

As luck would have it, the seas were calm and the parachutes got the fairing moving slow enough that it actually survived touchdown and was able to be recovered once the ship reached its location. The fairing is unlikely to be reused due to the issues outlined above, but it’s still a promising first step and will surely result in useful data for SpaceX to go over.

Revisiting 1960’s Spy Tech Space Catches

On August 19th, 1960 the US Air Force proved that mid-air recovery of an object returning from space was possible when a canister of film ejected from a Key Hole spy satellite was snatched by a C-119 “Flying Boxcar” as it descended under a parachute.

The first mid-air recovery in history

Due to the sensitive nature of the images being taken by these satellites, it was deemed that the best way to ensure the film was not intercepted before the US could reach it was to simply not let it land. The canister’s parachute slowed it down enough that pilots would be able to get a few tries at making the capture before it hit the water, but in the event that the film canister failed to be recovered by the aircraft they were designed to sink after 48 hours.

Catching a falling object from an airplane is an exceptionally difficult maneuver, and crews practiced constantly by catching dummy payloads that were dropped from planes flying above them. Being able to drop the film canisters directly onto a waiting Navy ship would have been much preferred, but in the early days of the Space Age that sort of reentry accuracy simply wasn’t possible. Indeed, occasionally they managed to get so spectacularly far off course that they would miss the ocean entirely; at least one film canister ended up landing in Venezuela.

Genesis: A High Profile Failure

Before anyone beats up on SpaceX for stumbling on a task that the US Air Force was able to accomplish with 1960’s technology, let’s not forget the high profile failure of NASA’s Genesis sample return mission in 2004.

Genesis wreckage in the Utah desert

The goal of Genesis was to capture solar wind particles and bring them back to Earth for study. Much like the fairing of the Falcon 9, the sample return capsule of the Genesis spacecraft was considered too fragile to land under parachutes.

Instead, the capsule was to be plucked out of the air by a helicopter flown by Hollywood stunt pilots. In an improvement over the 1960’s technology used for the Key Hole program, the Genesis capsule would be using a parafoil which allowed for controlled forward flight during the descent; the same type of parachute SpaceX is using to guide the Falcon 9 fairing towards their net.

Unfortunately, an incorrectly installed accelerometer meant the capsule’s electronics never deployed the parachutes. The capsule hit the ground at nearly 200 MPH in the Utah desert, though in the end scientists were able to recover enough material from the wreckage that all scientific goals of the mission were accomplished.

SpaceX’s Next Attempts

Credit: SpaceX

If recent history has taught us anything about SpaceX, it’s that you shouldn’t bet against them. While it won’t be the first time somebody has caught an object returning from space, when they finally manage to catch the fairing of the Falcon 9, SpaceX will surely be able to claim it’s the largest object to ever be recovered in such a manner. The inevitable social media blitz that will follow the first successful recovery should really be something.

Given SpaceX’s rapid launch rate and iterative approach to development, we likely won’t have to wait long to see the next attempt. Since the only net-equipped ship is on the West Coast, only launches from Vandenberg Air Force Base will be able to attempt a fairing recovery. A check of their advertised launch manifest for 2018 shows a number of upcoming launches from Vandenberg: the Iridium 5 launch currently scheduled for March 29th, followed by Iridium 6 sometime in April.

Nobody outside of SpaceX currently knows if fairing recovery will be attempted on these missions, but given the potential savings it seems unlikely they’ll be skipping any opportunities to try. The Falcon 9 fairing is estimated to cost $6M USD to produce, and due to its size and complex construction, has been identified as a bottleneck in an increasingly rapid launch cadence.

With nearly 30 more launches scheduled for 2018, and most of those requiring payload fairings, there’s plenty of incentive for SpaceX to make catching a school bus sized object as it falls from space seem as routine as landing a rocket on the deck of a barge.

38 thoughts on “SpaceX Joins in the Long History of Catching Stuff from Space

  1. “even the normally dramatic landing of the Falcon 9’s first stage was skipped”: I haven’t been able to find any explanation for this. The boosters are landed to save money, not (merely) for dramatic effect. Why didn’t they land this booster? Was the orbit such that they had to expend all its fuel?

    1. Because it was a Falcon 1.2 block 3, which was already reused and is an old design. Currently Space X is using the Falcon 1.2 block 4 and is close to introduce the block 5, that has some enhancements to simplify and make cheaper the refurbishing and reusing process.

    2. I might have mixed up what vehicle this was, but I think I may have read that landing-abort procedures were being tested, which explains why they didn’t just use it to get more safety data on vertical landings.

      The rocket being old and not rated for further reuse also makes a lot of sense.

  2. This thread would be remiss to not mention the KH-9 Hexagon spy satellite, launched 1971. It had six 500 lb film canisters that could hold up to 500 lbs of film. The canisters would detach, descend to earth, a drogue chute would open, and a helicopter would swoop in and snatch it mid air.

    There’s a great writeup on some of the successes and challenges (failed parachutes, some battery issues, and attempted salvages at 16,000 feet!) available from the CIA,

  3. Why can’t SpaceX keep the payload fairings attached to the 2nd stage and land them the same way the first stage is landed?

    I realize that it will have more orbital speed but you could easily use the spacecraft separation to deorbit the booster and bring it back for a controlled landing. Depending on mass of satellite vs. spent Booster you could get quite a bit of orbital kick to put the satellite into its final orbit, saving Fuel. Why waist all that energy that you used putting the booster into orbit by then just discarding it, I was thinking of a separation with recoil instead of the normal moving away slowly.

    And instead of The payload fairings opening up like a clam shell and pealing off, have them open more like a scissor or even on dual swing arms that rotate out and down and end up sitting along the sides of the 2nd stage rocket body with say tethers holding down the bottom ends so that they don’t come back up and hit the satellite when it is deployed.
    Eric D

    1. The main reason they can’t is “weight”; doing all that would add a ton (probably literally) of parasitic weight which would reduce payload capacity. The fairings detach pretty much as soon as the rocket is above most of the atmosphere, which means you don’t need to carry it any farther. It’s on just long enough to protect the payload from aerodynamic forces.

    2. They don’t currently recover the second stage, which you are right does have a lot more orbital velocity and a lot fewer engines.

      and I believe that they generally detach the fairings before the final second stage burn is finished, so that is now more mass for the second stage to accelerate, and then decelerate for a landing…

    3. I’ve seen other people suggest this actually.

      The main problem, beyond the fact that they don’t (currently, that MAY change down the line) recover the second stage of the Falcon 9, is that the whole point of jettisoning the fairing is to reduce weight. Keeping the fairings attached to the second stage would have a considerable impact on their capacity to LEO.

      Now on Falcon Heavy they’ve got enough lift capability that honestly it probably wouldn’t matter. But on single-stick F9 it’s unlikely they want to do anything to significantly reduce payload capacity now that they’ve finalized the Block 5 design and are really hitting their stride.

  4. I think I remember Gene Kranz writing in “Failure is Not An Option” that the Mercury or Gemini splashdowns were getting close enough that they decided to move the recovery ships lest a capsule crash onto the ship with a devastating impact on crew survival. Pun intended.

    1. Close enough to be a potential danger, and close enough to actually come down on the deck of a ship are too very different things.

      Gemini 9 did manage to come down within ~.5 miles of the target area, but on the other hand Gemini 5 splashed down ~170 miles away from where it was supposed to. So something of a mixed bag there.

      As late as the Apollo program, the capsules were coming down around 2 miles from the targeted splashdown point.

  5. Surely SpaceX has explored a lot of fairing return ideas and this is their least-worst option. I might have thought that, since the fairings are roughly half-cone/ogive shaped that a pair of pop-out tail fins and beavertail would turn it into a lifting body of sorts, sort of like the M2-F2. A waterproof semicircular curtain packed into the fixing ring could be drawn tight to keep the water out of the fairing (to some extent) just before spashdown.

  6. I believe Apollo Capsules were lifting bodies and were steerable.

    On the original topic – arent there two halves to the fairing? Are they going to catch both halves separately? With one ship?

    1. They generated aerodynamic forces that could be used to slow their decent and keep them in the upper atmosphere longer but they certainly weren´t lifting bodies in any sensible way.

      The capsules were balanced in such a way that they held an “average” angle of attack relative to the motion vector naturally. This angle of attack generated an aerodynamic force. By rolling the capsule along the Z axis, the vector of this lift force could be pointed above, below, left or right from the motion vector, thus steering the craft.

      You might find this NASA video about the Apollo Atmospheric Reentry interesting:
      (The bit about attitude/altitude control starts at roughly 10 minutes

      1. The Apollo computor vid after the one mentioned was also neat. Rope ROM. And amongst the remarks;
        “The moon is a light. You can’t land on it… and space is fake.”
        ROTF!!! 😂 Priceless! But then… noone has ever taken a picture of space. Hmmmm… 🤣

    2. It seems they are only attempting to recover one half of the fairing to begin with. Presumably when they get that working reliably, they’ll build another net-ship to grab the other. Plus they need to build them for east coast missions as well.

      I’ve heard some people theorize you could do both on one ship. Basically drop the first fairing half down on the deck and string up a new net before the second one comes in for a landing. But nobody external to SpX knows for sure at this point.

  7. On another note, the sheer cost of outfitting a boat w that net and all of the tracking… What is the price, nowadays, to put a satellite into orbit, and still break even on cost of doing so… And then there must be value added tax for such services… coorporate income, written off as R&D… ad nauseum. Or going through the back door… What is his car worth, and how much if we go get it and bring it back and sell it. It is obviously abandined.

  8. There was a proposal in the late ’60s to snag SATURN V FIRST STAGES out of the air in the same manner as the spysat film capsules. It was to be done with a truly monstrous helicopter to be built by Hughes Helicopter with something like a hundred-meter rotor disc powered by ramjets on the tips, sort of like the Sikorsky/Erikson Skycrane but five times the size.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s