Tycho Deep Space

Tycho Deep Space with attached Launch Escape System conceptual drawing. Kristian von Bengtson, July 2011.

 

Top: Tycho Deep Space fitted with Launch Escape System conceptual scetch by Kristian von Bengtson, July 2011. Bottom: Tycho Deep Space with crash test dummy Randy, August 11th 2012. Photo: Thomas Pedersen.

 

Tycho Deep Space (TDS), nicknamed Beautiful Betty, is the 2nd generation prototype space capsule made at CS. Along with the growth of the entire organization it has become possible to build and launch rockets bigger than initially anticipated. This in turn allows us to design a more traditional space capsule and thus the shape of TDS resembles that of the Apollo command module. An exploded view of the structure is seen below. The main structure is built in steel.

Exploded view of TDS1.

Exploded view of TDS1.

TDS has undergone several important tests as part of our efforts to develop a working space capsule that can provide life support for a single astronaut on a +100 km suborbital space flight. The last test performed with TDS was a combined Launch Escape System and parachute test. During this test TDS suffered a hard landing and substantial damage andhas now been retired.

TDS has a number of onboard systems, a schematic breakdown is shown below. It is equipped with a springloaded seating system that will maximize astronaut survivability in case of a hard landing. It is equipped with a parachute system consisting of a single drogue chute and three main parachutes, with a total area of about 150 square meter to provide a gentle landing. In case the capsule lands in a stable 2 position (upside down), the top of the capsule is equipped with four inflatable bags that will inflate and flip the capsule to a stable 1 position. TDS is also equipped with an Inertial Measurement Unit that calculates flight trajectory information, this is broadcast to Mission Control in real time via the onboard radio system. Furthermore TDS is equipped with a set of cameras and a video downlink.

Visio-tychoDS-1_flowchart01_oct2011.vsd

Development process

As part of the TDS development, a set of custom made parachutes were made and tested. Initial drop tests were conducted from the gantry crane at Lindø Industripark. Different slider configurations where tested to control the time it takes for the parachute to inflate. A slow inflation is desirable, as it results in a more gentle acceleration. When using the slower sliders, the 90 meter gantry crane proved to be insufficient in height though, as the parachute no longer had sufficient time to inflate before landing in the dry dock.

Setting up for drop tests from the gantry crane at Lindø. Photo: Thomas Pedersen.

Setting up for drop tests from the gantry crane at Lindø.

Fully inflated TDS parachute dropped from the gantry crane.

Fully inflated TDS parachute dropped from the gantry crane.

To overcome this obstacle, a manned test jump from 2 km altitude was also performed. This was performed by an experienced parachute jumper from Nordjysk Faldskærmsklub. During the jump Thomas also carried his regular parachute system consisting of a primary parachute and a backup parachute. Danish law prohibits a jumper to land in an experimental parachute, so Thomas cut the TDS parachute at about 1500 meter, deployed his primary parachute and landed safely at the NJFK airstrip. The test was a success and validated the chosen slider configuration.

TDS1-NJFK

Thomas Pontoppidan performs a manned jump with the TDS parachute, June 3rd 2012. Photo: Thomas Pedersen.

TDS drop tests

A series of drop tests of the TDS capsule were made at Lindø Industripark to investigate the impact performance and hydrodynamic stability. Nominal landing in parachutes is predicted to happen with a horizontal velocity of about 5 m/s and a vertical velocity of about 10 m/s. Thus the drop test setup was configured as a pendulum swing as sketched below. The capsule would swing forward 7 meter before being released from the cable, from which it would drop 5 meter vertical into the water. Two different orientations, A and B, where investigated to see how the pitch would affect landing and final stability.

Tycho Deep Space pendulum swing test. Basic setup diagram. Image: Kristian von Bengtson

Tycho Deep Space pendulum swing test. Basic setup diagram. Image: Kristian von Bengtson

Four drop tests were performed, and as seen on the images below, landing in orientation A resulted in a stable 1 condition, whereas landing in orientation B resulted in a stable 2 condition. There is no means for controlling how the capsule will actually land, so from this data there seems to be a 50/50 chance of getting the desireable stable 1 condition upon landing.

Drop test 1. Orientation A. Stable-1. Photo: Thomas Pedersen

Drop test 1. Orientation A. Stable-1. Photo: Thomas Pedersen.

 

Drop test 2. Orientation B. Stable-2. Photo: Thomas Pedersen

Drop test 2. Orientation B. Stable-2. Photo: Thomas Pedersen

The timewise evolution from impact to a stable position is deduced from high speed video obtained during the tests and is sketched below. When the capsule is pitched backwards relative to its motion vector (orientation A) the top of the capsule will continue forward during impact and the capsule ends in a stable 1 condition. If the lateral velocity is much higher than 5 m/s the top might carry enough inertia to tumble forwards into a stable 2 condition, this is however not tested. When the capsule is pitched backwards relative to its motion vector the leading edge carves into the water and the buoyancy forces it back up with such a force that the capsule rolls backwards into a stable 2 condition.

Drop orientation versus final attitude in water. Image: Kristian von Bengtson

Drop orientation versus final attitude in water. Image: Kristian von Bengtson

 

TDS1-splash

TDS drop test at Lindø Industripark, June 16th 2012. Image from fourth and final drop in orientation A. Photo: Thomas Pedersen.

In case the capsule ends up in a stable 2 condition it is fitted with four inflateable bags that will pop out from their compartments around the top of the capsule. This will generate sufficient buoyancy to flip the capsule. This was tested, but sadly not all bags inflated due to a short circuit in the system.

TDS with the uprighting bags only partially inflated.

TDS with the uprighting bags only partially inflated.

 

Launch Escape System and parachute trial

The capsule is equiped with a Launch Escape System which essentially is a rocket stage placed on top of the capsule. In case of severe problems during launch this LES system will engage, ignite the LES rocket engine and pull the capsule and astronaut away from danger. Such a LES is also found on top of the Apollo command module. The LES itself must undergo rigorous testing to evaluate its performance, thus the combined LES/TDS system was testfired from launch platform Sputnik. This also gives a unique possibility of testing the parachute system on the way down. The plan for the experiment is sketched below.

LES_seq01_660

Schematic illustration of the TDS/LES launch and parachute experiment. Graphics by Kristian von Bengtson.

The LES system will activate and propel the combined system to an altitude of roughly 1000 m. The LES will detach from the TDS capsule, the LES will fire a secondary rocket engine to move away from the capsule, the capsule will then deploy its parachute system and land safely. Meanwhile the LES will deploy a drogue chute and also land in the water.

TDS1-night

TDS with the LES tower mounted onboard launch platform Sputnik at Spaceport Nexø, August 11th, 2012. Photo: Thomas Pedersen.

 

The test was performed on August 12th 2012 in the Baltic Sea 30 km off the coast of Bornholm. All check-out procedures went smoothly and at approximately 9:15 AM local time, Beautiful Betty was launched. It went straight up but began to tumble and made a nice 360-degree loop. The LES tower separated down toward the water and the drogue and main parachutes were released, but Betty hit the water hard with its main parachutes not fully deployed. In short, all systems worked but the tumbling ate our potential energy and altitude for full main parachute deployment.

TDS1-launch

Lift off! TDS takes off from launch platform Sputnik. Photo: Thomas Pedersen.

 

The LES engine ignites and lifts TDS from the Sputnik launch platform.

The LES engine ignites and lifts TDS from the Sputnik launch platform.

From what we can tell, all flight systems worked fine except deploying the uprighting bags, which we could not activate by radio after high-impact splash down. We were not allowed to separate the LES tower until it finished burning — or else it could fly somewhere outside the range safety area. When commanded, the separation took place and all explosive bolts worked and the tractor engine fired.

Right after the drogue was released, the capsule top-part descended slowly toward the ocean using a tiny parachute. Since there was no time to get Betty stabilized using the drogue, we had to release the main parachutes, which worked fine as well. The bags were simultaneously pulled by the drogue but the tumbling of Betty seemed to have some kind of effect on the synchronous deployment of the parachutes. One parachute was almost deployed completely. The rest barely made it outside the bags. The flight is summarized in the montage below.

Main events in flight. Image: Thomas Pedersen / Morten Bulskov. Edited: Kristian von Bengtson

Main events in flight. Image: Thomas Pedersen / Morten Bulskov. Edited: Kristian von Bengtson

After flight both the LES engine and TDS where recovered by CS recovery crew and the crew of Naval Home Guard vessel MHV 903 Hjotø.

Betty during recovery with Per Siebeneicher in the chute chamber. Photo: Thomas Pedersen

Betty during recovery with Per Siebeneicher in the chute chamber. Photo: Thomas Pedersen

Tycho Deep Space took significant structural damage during impact, the pressure hull suffered a minor hole with a minor water intake as a result.

Designing, building and flying TDS with the LES system has taught us an enormous amount of things on practical capsule and system design. TDS is now retired.

TDS on mission control vessel MHV903 Hjortø. Photo: Thomas Pedersen

TDS on mission control vessel MHV903 Hjortø heading back to Spaceport Nexø. Photo: Thomas Pedersen

 

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