Asteroid Size

{
  "absoluteMagnitudeH": 19.09,
  "albedo": 0.35,
  "asOf": "2026-10-11T08:41:41.604Z",
  "degraded": false,
  "diameterKm": 0.342,
  "diameterM": 342,
  "disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
  "formula": "D(km) = 1329 / sqrt(albedo) * 10^(-H/5)",
  "impact": {
    "densityKgM3": 2600,
    "diameterKmUsed": 0.342,
    "energyHiroshimaEquivalents": 173000,
    "energyJoules": 10900000000000000000,
    "energyMegatonsTnt": 2590,
    "massKg": 54300000000,
    "speedKmS": 20
  },
  "notChecked": [
    "real shape: this treats the body as a sphere",
    "the real albedo when none is given: sizes are uncertain by a factor of about two",
    "…2 more"
  ],
  "reasons": [
    "Size from magnitude is only as good as the albedo: dark bodies are much larger than bright ones at the same H."
  ],
  "source": "computed locally",
  "summary": "H 19.09 with albedo 0.35 gives a diameter of about 342 m. At 20 km/s and 2600 kg/m3 a body of 342 m carries about 2590 megatons of TNT of kinetic energy.",
  "verdict": "COMPUTED"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://space-objects.x402tookit.com/asteroid-size?H=19.09&albedo=0.35&velocityKmS=20'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - 'https://space-objects.x402tookit.com/asteroid-size?H=19.09&albedo=0.35&velocityKmS=20' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode

// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.02 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.02" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.02 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fspace-objects.x402tookit.com%2Fasteroid-size
const res = await pay("https://space-objects.x402tookit.com/asteroid-size?H=19.09&albedo=0.35&velocityKmS=20");
console.log(res.status, await res.text());

# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.02 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.02"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://space-objects.x402tookit.com/asteroid-size?H=19.09&albedo=0.35&velocityKmS=20")
    print(res.status_code, res.text)