The price corridor
Backing below, cost of entry above, the market in between.
The protocol does not set the market price of ASTRX and cannot set it. It sets two other figures, and the market price lies between them.
Below sits the backing — the share of the reserve that falls to one token. This level is held up by redemption, which is open at all times: a holder exchanges tokens for a proportional share of the reserve, less the redemption fee, whenever he likes. This is not an undertaking to buy the token back at some price, but a consequence of the design — the reserve belongs to the holders, and the way out of it does not close under any circumstance.
Above sits the cost of entry — the price at which the contract mints a new token. Anyone may enter at any time at that price, so there is no reason to pay substantially more on the market than entry costs.
How it behaves
Schematic. Both boundaries move; the market price is wherever the market puts it between them.
Both boundaries are maintained by arbitrage, without any action by the protocol. Above the cost of entry, minting is cheaper than buying; below the backing, redeeming is better than selling. The market price is kept between the two by whoever notices first.
Where the price sits inside the corridor is settled by the market, and the protocol does not interfere with it. It can sit near the ceiling; it can fall towards the floor. What the contract does is move the ceiling up and defend the floor. How it does each is set out on the next two pages.