function battleRemove(uint256 _tokenId) public onlyOwnerOf(_tokenId) {
    require(spaceships[_tokenId].battleMode == true);

    spaceships[_tokenId].battleMode = false;

    balances[msg.sender] = balances[msg.sender].add(spaceships[_tokenId].battleStake);

    emit EventBattleRemove(msg.sender, _tokenId);
  }