Testing Progression

During testing of both Starship and Superheavy, many signs are noticed, including venting at the tank farm. At this page, the activities are listed below. Please note that these are based on pervious tests, and they may change.

### Road closure

Highway 4 is closed, evident by a police car stopping at the highway and putting a blocker on the road. During a test of the vehicles, the beach must also be closed. Only SpaceX employees are permitted to pass the road closure.

### Beach/pad clearance

All SpaceX employees leave the launch site, and the beach must be cleared before testing progresses. The clearance of the site is a sign of vehicle testing, rather than rollouts or such.

### Tank farm activity

Activity of the tank farm is evident when venting occurs near visible tanks. Both the suborbital and orbital farms have three sides: LN2, LOX, and CH4. The tank farms cool the propellants to a liquid so much more of it can fit into the vehicle.

Usually, the LOX subcoolers become active first, then the CH4 subcoolers (if a engine ignition will be attempted). In a cryo proof test, the LN2 subcoolers become active. The activity of the tank farm may stop and start again repeatedly during testing. This phase can begin between less than an hour and several hours before an engine test, depending on how much propellant will be loaded into the vehicle. For a test on the OLM, the OLM begins venting before product loading, and the vent stops just before loading begins.

### Product load

The loading of cryogenic products is evident when condensation (seen as a change in color) becomes visible, followed by frost accumulation on the vehicle. There may also be venting on the vehicle during and after propellant load, as the vehicle regulates it's tanks' pressures. The tank farm then spools down as loading finishes. It is possible for no visible signs of loading to appear. In a cryogenic proof test, the vehicle detanks after this stage.

An engine test can occur in as little as around half an hour after product loading, but is delayed by larger amounts of propellant being loaded into the vehicle.

### Engine chill

In a Starship, engine chill is evident when two vents start exhausting liquid oxygen, and usually means an engine test will occur in about 10 - 20 minutes. In a Booster, it is evident when a ring on the orbital launch mount becomes frosty, followed by a distinguished vent. The T- on a Booster is currently unknown.

Engine chill usually persists after the engine test, and may start and stop as the vehicle drains of propellant.

### Imminent signs of testing

In a static fire test, a siren is reported 5 - 10 minutes before the test, and functions as a warning to Boca Chica residents of a potential overpressure if an explosion were to occur.

Around 30 seconds prior to a Starship engine test, an upward venting from the engine chill vents is seen, and a stream of water under the vehicle also starts if the test will be a static fire test. For a Booster, the water stream occurs in an unknown time, due to it being never used before, and just installed. However, during booster testing in Summer 2022, a new short vent was spotted on the OLM near the booster QD, sometimes refered to as "burst" vent. A test would then be 30-40 seconds away.

### Engine test

A number of engines now undergo testing.

**Spin prime test:** The engines shoot out a stream of liquid oxygen to spin the pumps without ignition.
**Preburner test:** The engines produce a fireball without much thrust.
**Static fire:** The engines ignite with large amounts of thrust and combustion.

Engine chill continues after testing, and the vehicle may test the engines again after a while, with or without detanking.

### Detank

The first sign of the vehicle being drained of propellant is a long vent on the vehicle. A stack may then begin venting, and the tank farm spools up again. Frost may again, but often unevenly and/or suddenly. Engine chill spools down and then stops, while frost begins receding. The vehicle will vent more during the draining process, as it continues to regulate pressure.

### Site reopening

Once the vehicle is drained of propellant, the road is reopened, at first to SpaceX employees, then to the public. The vehicle may continue to vent periodically after the road is reopened.