Introduction
Every Mars mission relies on a perfectly packed parachute to slow the spacecraft during atmospheric entry. That massive chute, often folded into a donut-shaped bag, must deploy flawlessly millions of kilometers from home. This step-by-step guide walks you through the essentials of packing a Mars parachute—just as engineers at NASA’s Jet Propulsion Laboratory do. Whether you’re a budding aerospace enthusiast or a seasoned engineer, these steps will help you understand the precision required to turn a billowing canopy into a compact, reliable bundle.
What You Need
- Mars parachute (disk-gap-band or similar design, typically 30–50 m diameter)
- Donut-shaped deployment bag (made of Kevlar or high-strength fabric)
- Pilot chute or mortar system (for initial deployment)
- Rigging lines (suspension lines, risers)
- Sealant tape and zipper closure (for bag sealing)
- Cleanroom environment (Class 100,000 or better)
- Inspection tools (magnifying lamp, line tension meter)
- Pack weights (to simulate mass during packing)
- Documentation sheets (for serial numbers and packing notes)
Step-by-Step Instructions
Step 1: Inspect the Parachute and Bag
Lay the parachute flat on a clean, static-free surface. Check every seam, gore, and suspension line for damage, fraying, or contamination. Use a magnifying lamp to spot micro-tears. Examine the donut bag—its inner and outer walls must be free of punctures and the zipper mechanism must slide smoothly. Record serial numbers and any anomalies in your log.
Step 2: Prepare the Packing Area
Set up your cleanroom table with pack weights, line tension meter, and sealant tape. Confirm the temperature and humidity are within specified ranges (typically 20–25°C, 30–50% RH). Arrange the donut bag so its opening faces you, and position the pilot chute or mortar assembly nearby.
Step 3: Flake the Canopy
Starting from the apex (top center) of the parachute, flake the canopy fabric into a long, even strip. This process, often called “flaking,” ensures air can flow evenly during inflation. Fold the fabric in accordion-style pleats about 1 meter wide. Work slowly to avoid creases. Use pack weights to hold each fold in place. Aim for a stack that is slightly smaller than the inner diameter of the donut bag.
Step 4: Bundle the Suspension Lines
Gather the suspension lines and lay them in parallel rows. Use a line tension meter to ensure each line carries equal tension—this prevents twisting. Tie a temporary lacing cord around the bundle every 50 cm to keep them organized. Leave a 30 cm tail at the end for later attachment.
Step 5: Insert the Canopy into the Donut Bag
With the donut bag laid flat, carefully place the flaked canopy into the bag’s interior. The bag is shaped like a thick ring; the parachute should fill the central cavity. Work the fabric in from the bottom, smoothing out any bunching. Avoid letting the fabric touch the bag’s zipper—use a protective liner if available. Once the entire canopy is inside, tuck the apex end toward the center.
Step 6: Pack the Pilot Chute (or Mortar)
Smaller Mars parachute systems use a pilot chute to pull the main chute from the bag. If using a mortar, insert the packed pilot chute into its tube. Secure it with shear pins (for mortar) or a retaining lanyard (for pilot chute). Attach the pilot chute’s bridle line to the parachute’s apex via a quick-release loop. For mortar systems, ensure the gas cartridge is seated correctly.
Source: www.space.com Step 7: Route the Suspension Lines
Feed the suspension lines through pre-cut channels or grommets on the donut bag’s outer edge. Each line should exit the bag at the designated point. Use a lacing needle to thread lines that must cross over the bag. Attach them to the spacecraft’s attachment points (risers) using locking carabiners or sewn loops. Double-check all connection points.
Step 8: Close and Seal the Bag
Zip up the donut bag’s closure completely. Apply sealant tape along the zipper track to prevent dust ingress. Reinforce stress points with Kevlar patches if needed. Use a vacuum bag sealer to remove excess air from the interior—this reduces volume and prevents fabric shifting during launch. Weigh the assembled pack to confirm it meets mass specifications.
Step 9: Final Inspection and Documentation
Photograph the packed parachute from all angles. Check that no suspension lines are pinched or twisted. Test the pilot chute’s deployment spring (if applicable) by gently pressing it—it should have a clean snap. Log the pack date, technician name, and any deviations. Store the packed parachute in a clean, temperature-controlled container until integration with the spacecraft.
Tips for Success
- Work in pairs: Parachute packing for Mars requires at least two technicians to handle the large fabric and line bundles safely.
- Control the environment: Even a single fiber from a cleaning cloth can snag a suspension line. Wear cleanroom suits and use anti-static mats.
- Practice flaking: The flaking step is the most error-prone. Use a practice parachute (same material but cheaper) to train before packing flight hardware.
- Don’t skip bag alignment: The donut bag’s orientation must match the spacecraft’s mounting. Mark the bag with an arrow indicating the “top” (closest to the backshell).
- Document everything: Mars parachute failures have occurred due to small errors like a misplaced line. A thorough log helps troubleshoot if something goes wrong.
- Test the deployment sequence: Before final integration, run a partial deployment test in a cleanroom vacuum chamber (if available) to verify the packing method.
By following these steps, you’ll ensure the parachute deploys reliably when it’s most needed—during hypersonic descent through the Martian atmosphere. The donut-shaped bag may look like a giant cake ring, but it’s the key to a successful Mars landing.